JPS585059A - Loop transmission system - Google Patents

Abstract

PURPOSE:To allow a simple device to decide priority and to prevent data collision between plural stations, by allowing each image processor to transmit its station data when receiving a packet from a specific station which serves as a temporary master station during system actuation. CONSTITUTION:When terminals A, B, C, and D are powered up, the terminal A serves as a temporary master station firstly to issue a command empty packet. This command empty packet is transmitted through a transmission line 1 to the terminal D, which once knowing the said packet is empty, writes abit for showing that the loop is being connected, its station address (D), and the address of a transmission destination in the packet and then sends it to the terminal C when a transmission request is given. Further, said packet is transmitted to the terminals B and A successively and if the address of some terminal coincides with said transmission denstination address, the packet is fetched to return an answer signal to the transmitting origin terminal D. When the terminal D has no transmission request, the empty command packet is transferred to the trailing terminal C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention connects a plurality of m-image processing devices with a signal transmission member,
By sequentially transferring packetized information, 5iIis
A loop transmission system VC911 is used for transmission.

Recently, optical fibers have been put into practical use as optical transmission members, and instead of transmitting information as electrical signals, attempts have been made to transmit information converted into optical signals using optical fibers as a medium. According to such a transmission method using optical fiber, the signals to be transmitted are not affected by external influences such as electromagnetic induction, and high-speed transmission is possible. Jlt7 AIVA has advantages such as being lightweight and easy to install.

A system in which a plurality of terminals are connected in a loop using optical fibers has been proposed. In such a system, when packets are sent from multiple terminals all at once, it is necessary to determine the priority of each device in the system as a way to avoid collisions on the loop, and a discrimination circuit is required. It is also not easy to change.

In view of the above points, the present invention provides a loop transmission system in which a plurality of 1m image processing devices are connected in a loop through a signal transmission member, and image transmission is performed by transmitting packetized information. By setting an image processing device capable of generating information packets in the system, and making it possible for each image processing device to output information on the loop only when it receives the above packet, the information output in the system can be improved. The purpose is to prevent information collisions on the loop.

Below, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a diagram showing connections in an embodiment of a loop transmission system using optical fibers to which the present invention is applied. A schematic explanation will be given using FIG. Hereinafter, the packetized image information will be referred to as an image packet, and the packetized control information will be referred to as a command packet. A, B, C, and D are terminals, which are equipped with a document image reading unit equipped with a solid-state image sensor such as a COD', an image recording unit, and an optical-to-electrical converter (hereinafter referred to as 0/ This image processing device has an electric-to-degree optical converter (hereinafter referred to as an E10 converter). As shown in the diagram, terminal A,
B, C and D are connected in a loop by two parallel optical fibers. 1 is a packet line through which command packets and image packets are transmitted; 2 is a transmission line with a clock synchronized with the packets of packet line 1; That is, the system of this embodiment has a configuration in which command packets and image packets are transmitted through a common optical fiber, and high-speed transmission can be achieved by packetizing information and transmitting it.

When the system is started, that is, when power is turned on to each terminal, a command packet (hereinafter referred to as "empty") (hereinafter referred to as "kerato") having no information is transferred through the loop. Also, this sky (Kuro synchronized with Kerato, Ri is clock line 2)
The above will be transferred. When the system is started, there is one terminal that can issue this empty certificate and one master terminal is preset. In the system, one Soranoku Kerat issued from one master terminal at one location is sequentially transferred to the terminals, and the terminal forms the control information necessary for this Soranoku Kerat and sends it on the loop as a command nok Kerato. It is designed to be transmitted.

, and one ノ(ke) being forwarded the loop.

Each terminal can issue a command packet only when the terminal inputs the command packet. This prevents command information from being output from multiple terminals simultaneously on the loop. Furthermore, the terminals that can issue command packets when the system is started can be arbitrarily set. Note that each terminal determines the input of a packet based on the input of the black and white signals transmitted by the black and white lines 2. On the other hand, image packets are transmitted after mutual understanding is obtained between the sender and the receiver using command packets, so only the command packets are transferred on the loop when the device is started.

In the system shown in FIG. 1, terminal A is assumed to be a master terminal that can issue a command packet when the system is started. Now, when terminals A, 'B, 'C, and D are powered on, a command packet is first issued from terminal A and transmitted to the terminals. This command packet is normally an empty packet, and the signal on packet line l is "0", but the input of the command packet is recognized by inputting a clock synchronized with the command packet from clock line 2 to the terminal. Ru. The terminal analyzes the input command packet, and if it finds that it is an empty packet, it then sends the command packet to the terminal.
It is confirmed whether or not there is a transmission request from the user, and if there is no transmission request, an empty packet containing only black and white packets is transmitted to terminal C. However, if there is a transmission request to the terminal, the input empty packet contains a bit indicating that a loop connection is in progress, the address of the terminal that should send the image, the address of the terminal that sent the image (in this case, the terminal's address), and the address of the terminal that sent the image. Bits corresponding to information such as the number of transmissions and image size are set and transmitted to terminal C, after which a response to the command from the destination is awaited. The command packet, which was an empty packet at this point, has become a command packet containing the above-mentioned control information. Terminal C similarly analyzes and issues command packets, and further transmits the command packets to terminal B. Terminal B performs the same operation and becomes the terminal person.

When the terminal A is connected to the terminal, the command packet is transferred in one direction on the loop. It is clear from the above that when the system starts up, the only terminal that can issue command packets is set as the master, and after that, each terminal can only issue command packets when it receives command packets. As mentioned above, no information collision occurs on the loop.

Each terminal A, B, C, and D is equipped with a timer.
This timer constantly detects loop breakage. This will be explained below.

Loop breakage refers to situations such as when one of the terminals is not powered on or when the optical fiber itself is cut. In the case of a loop transmission system, it is clear that all connected terminals and all optical fibers must be in perfect condition for the system to function. Furthermore, if the system is normal, the packet will definitely go around the loop once within a certain time after the packet is issued, and will be input again. This fact is utilized to detect loop breakage. When the power is turned on, terminal A, which is the only master capable of issuing command packets at the time of system startup, immediately issues command packets and starts counting the built-in timer. Thereafter, if no command packet is input within a preset timer operation period, it is determined that the loop has been broken. The other terminals B, O, and D start counting their timers after power is turned on, and if no command packet is input within the timer operation period set for each terminal in advance, or they output a command packet for the first time. After that, if the next command packet is not input within a certain period of time, it is determined that the loop has been broken. In addition, 1. After the system is started, if the system loop is disconnected for some reason during system operation, all terminals will start a timer to output and measure packets, and will output the next packet within a certain amount of time. Always detects whether or not is input.

Thereby, there is no need to perform a dedicated grotocall for detecting loop breakage, and no dedicated circuit is required for this purpose. As mentioned above, the terminals that can issue command packets at the time of system startup can be set arbitrarily. According to this setting, the set time of the timer for loop disconnection detection is determined for each terminal. According to the present invention, by packetizing and transmitting information in a loop transmission system, not only high-speed transmission is possible, but also information collision avoidance on the loop, loop disconnection detection, etc. can be easily achieved. can.

FIG. 2 shows image reading units (readers) provided at terminals A, B, O, and D. In the main scanning 9 copies, A4 size originals are sub-scanned in the horizontal direction, and A3 size originals are sub-scanned in the vertical direction. Has resolution. Therefore, main scanning 1
The number of pits on the line is 16. Bit/llX297 Dragon=
It is 4752 bits, and the sub-scanning is 16 lines in A4 size - 210m width and 3360 lines in A3 size, which is twice as large as 6.
There will be 720 lines. As shown in Fig. 2, two photoelectric converters 0CDI arranged in the main scanning direction convert the reflected light from the original O illuminated by the fluorescent lamp 2 through lenses L1 and L2.
and 00D2, the image of document 0 is divided into two, read, converted into electrical signals, and further sent to adder P to form image information of the fil line. In this way, 3360 lines (A
4 size) or 6720 lines (A3 size).

As mentioned above, the image information is electro-optically converted and transmitted as image packets through optical fibers. Figure 3 shows an image packet. As shown in the figure, the image packet is synchronized with the clock transmitted by the clock line 2, and the data changes when the clock rises, and the clock falls at a stable point in the middle of the data.

An identification signal S is added to the head of the image packet, and a dummy clock DOL is formed at clock line /2. The identification signal S is a control signal for distinguishing between an image packet and a command packet transmitted to the packet line, and is an rlJ signal when the packet is an image packet, and an rOJ signal when the packet is a command packet.

This identification signal is entered into the terminal before the packet is sent, and each terminal receives the following information (Image packet is frame 7)
'Determine whether it is a packet and perform the specified processing.

FIG. 4 shows a command packet. As mentioned above, a dummy clock, DOL, is added to the clock line 2 at the beginning of the command packet, and an identification signal S, which is a "0" signal, is added to the packet line. It is synchronized with the clock.

Data changes at the rising edge of the clock. Note that the command packet has a 32-pit configuration as shown in the figure. FIG. 5 shows the details of the 32 bits of the command packet. 1st~
The 4th bit is the setting of the first destination address, and the 5th to 8th bits are
The bits are used to set the number of transmissions to the first destination, and the 9th to 12th bits
Bits are the setting of the second destination address, 13th to 16th
Pitt sets the number of transmissions to the second destination, the 17th to 2nd
The 0 bit is used to set the source address. Second
1 bit is "1" in the size setting of the image information to be sent.
The signal is A3 size, the button signal is A4 size.
Bit 2 is a bit used by the sender to ask the destination whether it is ready to receive image information, and is functional in the case of the rlJ signal. The 23rd bit is a bit that signals the start of transmission of image information and functions with a "1" signal. The 24th bit is a bit used by the sender to ask the destination if the reception of the image information is complete, and it functions with a "1" signal. The 25th to 29th pits are blank. The 30th bit is a response bit from the first destination in response to the command from the receiving source, and when it is ``1'', it indicates acceptance of the command.

The 31st bit is the response bit from the second destination and is “1”.
” indicates acceptance of the command.

The 32nd bit is a bit indicating that a transmission request has been issued from one of the terminals in the system and that the terminal is connected to the loop, and when it is ``1'', it indicates that the terminal is connected.

In this way, one command packet has the function of specifying multiple destinations, the function of transmitting responses from them, the function of specifying the number of transmissions to multiple destinations and the image size, and the function of preparing for reception from the source to the destination. Complete, start sending,
It has a function of inquiring or instructing completion of reception.

FIG. 6 shows an example of how the system shown in FIG. 1 is used, from terminal A to terminal B, C! , D show the procedure of a protocol related to image transmission when different numbers of image information are transmitted. Lock, each terminal's AT L/S and C terminal A is 1000
, terminal B is 0100, terminal C is 1100. The terminal number is fixed as 0010. To describe a specific usage example, image information is transmitted from terminal A to terminal B, one image to terminal C, two images to terminal C, and three images to terminal R in A4 size.

Terminal A, which received the empty packet in (1), sets rlJ in the loop connection of the command packet, and
Enter terminal B's address "o1o6" as the destination, terminal C's address "11oo" as the second destination, and set 1, the number of sheets to be sent to terminal B, which is the first destination, in binary notation [1
000j, the number of sheets to be sent to terminal C, which is the second destination, is set to ``oloo'' in binary notation, and the image information size is set to A4 and ``1'' to form a command packet.

Then, in (2), it is transmitted to the terminal. Since this command packet is irrelevant to the terminal, it is transmitted to terminal C as is in step (3). Terminal C analyzes the command packet, and if it is understood, sets the response bit of the second destination to "1" and transmits it to terminal B in step 4). Terminal B analyzes the command packet, and if it is understood, sets rlJ in the response bit of the first destination and transmits it to the terminal person in step 5). Terminal A analyzes the command packet, confirms the responses from the first and second destinations, sets the first destination to the terminal's address 0010, and leaves the second destination blank. In addition, the number of sheets to be sent to the terminal, which is the first destination, is 3 in binary notation [001
0J, the number of sheets to be sent to the second destination is left blank, the image size remains A4, and a command packet with rlJ set is transmitted to the terminal at (6). The terminal analyzes the command packet, and if it is understood, sets the response bit of the first destination to "1" and transmits it to terminal C in (7). Since terminal C is unrelated, the data is transmitted to terminal B as is in (8). Terminal B is also unrelated, so it is transmitted directly to the terminal user in (9). When terminal A confirms the response from the first destination, it then uses a command packet to specify terminal B as the first destination and terminal C as the second destination, and sets the bit that asks whether it is ready to receive image information. 1" and transmit it to the terminal using α. Since the terminal is irrelevant, it is transmitted directly to terminal C using αυ. Terminal C analyzes the command packet, and if it is ready for reception, sets the response bit of the second destination to "1" and then transmits it to terminal B. Terminal B analyzes the command packet, and if it is ready to receive it, sets the first destination's response bit to "1" and transmits it to the terminal person via α. When terminal A analyzes the command packet and confirms that the first destination B and second destination C are ready for reception, terminal A sets the new nine to D for the first destination and receives the second destination blank. Sets the bit "1" to inquire about the completion of preparation, and transmits it to the terminal at B4). The terminal analyzes the command packet, and if it is ready to receive it, it sets the response bit of the first destination to "sect l and B5.
) is transmitted to terminal C. Terminal C is irrelevant, so it transmits it to terminal B as it is at αe. Terminal B is irrelevant, so it transmits it to terminal person as it is at αη. When terminal A confirms the response from the first destination, it sets the transmission start bit to "1" in the command packet, and then sends terminal B and second destination to the first destination.
Specify terminal C as the destination and transmit to the terminal using B8. a9
~ (In 2D, similar to the above-mentioned nine sequences, this command is transmitted sequentially to terminals C and B, and is analyzed, set as a response, and transmitted to the terminal person. Terminal A is sent to terminal B. After confirming the responses from and C, specify the terminal as the first destination, set the transmission start bit to “1” (22
1 to transmit to the terminal. In (c) to (c), similar to the sequence described above, this command packet is sent to the terminal, O,
The data is sequentially transmitted to B, analyzed, a response bit is set, and transmitted to the terminal person. Terminal A is checked for a response from the terminal. Up to this point, terminals B, O, and D, which are the destinations, are ready to receive images.Next, terminal A reads the first document and forms an image packet, and performs steps (a) to (b). This image packet is sequentially transmitted to the terminal as O and B.

At this time, both terminals C and B capture the image information of the original. When the first image packet is input to the terminal at (to), terminal A reads the second document and forms an image packet. , B are transmitted sequentially. At this time, terminal C captures this image information. Terminal B does not capture the image information and transmits it to the terminal as it is by □□□. When the second image packet is input to terminal A,
reads the third document and forms an image packet, and from (B) to (To) this image packet is sent to the terminal and O
and B are transmitted sequentially.

Only the terminals take in this image information, and terminal C directly transmits the image packet to terminal B, and terminal B directly transmits the image packet to terminal A. In (b), the third image packet is input to the terminal person.

As a result of the above, one card is sent from terminal A to terminal B, and two cards are sent to terminal C.
Image information for three images was transmitted to each terminal. When the third image packet is input, terminal A specifies terminal B as the first destination and terminal C as the second destination in command bag 7), and also sends a bit that asks whether the reception is complete. Set "1" to "1" and transmit to the terminal at (to). This command packet is sent to the terminal at 0I-0υ, C and B are transmitted sequentially, and when terminal A confirms the responses from terminals B and C, terminal A specifies the first destination terminal and receives the command packet. Ask whether it is complete, ) set rlJ
(Transmit to the terminal at 45.

This command packet is (43 to (451) terminal, O
and B are transmitted in sequence, and when terminal A confirms the response from the terminal, the glot call for all image transmission ends. Then, in (46), the empty packet is transmitted again from terminal A to the other terminal. Thereafter, the empty packet is sequentially transmitted to terminals A, D, 0, and B, and waits for the next transmission request. In this way, before transmitting image information, all terminals are prepared for reception, and then the image information is transmitted to multiple devices at the same time, making effective use of the transmission speed of optical fiber. This enables high-speed transmission.

Also, if the terminal is not specified as the destination by the command packet, this terminal does not perform any processing on the input image packet and transmits it to the next terminal.
Transmission of different numbers of image information for each terminal can be performed by the same operation as when transmitting image information to all terminals.

Furthermore, since each terminal's response to the control information in the command packet is confirmed before proceeding to the next step, erroneous transmission of image information will not occur.

Next, when an empty packet is transferred on the loop -C, 2
The priority level when more than one terminal has a request to transmit image information will be explained below. As an example, a case will be described in which transmission requests are issued from terminals A and B in FIG. Now, if terminals A and B have transmission requests when an empty packet is input to the terminal, the empty packet is sent from the terminal to the terminal C.
Then, it is further transferred to terminal B. In other words, the information is input to terminal B before being input to the terminal person. As a result, terminal B has the right to become the transmission source before terminal A, since the empty packet is sent with the loop-connected bit at terminal B.

In this way, the terminal connected to the output side of the terminal that currently outputs the empty packet has the highest priority, and the priority gradually decreases according to the order in which the empty packets are transferred, and the terminal that is connected to the input side of the terminal that outputs the empty packet has the highest priority. The connected terminal has the lowest priority. Maroku.

If an image is currently being transmitted and another terminal receives a request for transmission, the current transmission operation ends and the terminal that was the source of the image information outputs an empty packet. The terminal connected to the output side of this source has the highest priority, and the terminal connected to the input side has the lowest priority. That is, at the time when the previous transmission of image information is completed, the priority of the loop related to the next transmission is automatically determined based on the previous transmission source. As mentioned above, the priority changes from moment to moment.

FIG. 7 shows a circuit embodiment of a terminal of an image transmission system according to the present invention. Reference numeral 11 denotes an optical-to-electrical converter (hereinafter referred to as an O4 converter) provided at the input section of the terminal, which converts information input as an optical signal from a signal transmission line using an optical fiber into an electrical signal. 12 is a command/image discrimination circuit O
As described above, the electric signal input from the A converter 11 is ANDed with the identification signal S added before the packet and the clock to determine whether the input packet is an image packet or a command packet. If it is a command packet, it outputs a "1" signal to line 13, and if it is a command packet, it outputs a "LJ times signal" to line 14. Also, it outputs a packet with the identification signal S removed to line 15.16
is a recording unit that records images based on input image packets, and an image packet that reads originals and converts them into electrical signals.

This is the reader/printer section that forms the page. line 17
is a non-source signal line to which a "1" signal is always output when this terminal is not the source of image information. 18 and 1
9 is an AND circuit, and when the AND circuit 18 receives the "1" signal on line 13 from the command/image discrimination circuit 12 and the "1" signal of the non-source signal on line 17; Outputs the input image packet to line Mikami. Also, the AND circuit 19 is supplied with “1” on the line 13 from the command/image discrimination circuit 12.
” signal is input, outputs the command packet input by line 15 onto line 21. If the terminal is the source of image information, the non-source signal on line 17 is a "0" signal, which prohibits output of input image packets to the line. This results in 1
If the image packet is an image packet, the image packet output on line 20 is the input line to the league printer device 16. The signal is branched to a line input to a delay circuit 22. Delay circuit 22
is provided to delay the image packet in order to form the identification signal S, since an identification signal must be added before the image packet in order to output the image packet to the next terminal. Reference numeral 23 denotes an image identification signal generation circuit which, when inputting the line 13 rlJ signal, generates an identification signal to be added in front of the image packet currently being input. 24 is an OR circuit which passes the identification signal S of the "1" signal output from the image identification signal generation circuit 23 to the delay circuit 22.
In addition, if the terminal is the source of the image information, the reader and printer device 1
An identification signal S is applied to the image information output from 6 onto line 33.
026, which is attached to line 25 and output to line/25, converts the image packet input via line 25 into an optical signal using an electric-to-optical converter (hereinafter referred to as ψ converter) installed at the output section of the terminal, and converts it into an optical signal. It is transmitted to the next terminal using fiber as a medium.

On the other hand, if the input command is a command number, the command number output on line 21 is input to the input command register 27.

The input command register 27 stores all 32-bit command packets. 2B is a command analysis and generation circuit, which processes the image signal (kerato discrimination signal) outputted on line 13 and the command signal outputted on line 15.
O input command register 2 to which the Kerato discrimination signal is input
When it is determined that all 32-bit command kerato has been input in 6, it takes in all of these 32-bit command kerato, analyzes its contents, and then forms response bits and specified bits as necessary as described above. Then, all 32 bits are set in the output command register 29 at the same time. Further, when the terminal mentioned above is not the source, a non-source signal is output on line 17. 030 is a command identification signal generation circuit, and an identification signal S is added before the command no.
031 forming the output command register 2 is an OR circuit.
Command input from 9.

An identification signal S from the command identification signal generation circuit 30 is added to the front of the packet and output to the line 32. Line 32 is input to a converter 26.

Like the image packet, it is converted into an optical signal and transmitted to the next terminal via the optical fiber used to transmit the image packet.The four switches 8W1 to SW4 provided in the command analysis and generation circuit 28 are The switch SW5 is used to set whether or not a command (kerat) can be issued when the system is started, and is operated by the only terminal in the system. 0 These five switches are preset when the system is installed, and there is no need to re-operate them unless a special problem such as system improvement occurs.0 Figure 8 is shown in Figure 7. 60 is an address bus, '61 is a data node, 62 is a read signal line, and 6 is a detailed circuit diagram of the command analysis and command generation circuit 28.
3 is the light signal line.

Reference numeral 40 denotes a central control unit (hereinafter referred to as CPU) which controls the operation of the circuit shown in FIG. 8, and is, for example, an Intel 8085 microcombinator. Reference numeral 41 denotes an interrupt controller, such as Inchil Corporation 8259, which inputs an interrupt signal to the CPU 41 for controlling interrupts of the CPU 40. The CPU 40 operates when there is an interrupt input from the interrupt controller 41.The signal input to the interrupt controller 41 is the aforementioned timer for detecting loop breakage; A signal (INT2) indicating that a key of the provided operating section has been operated.Command discrimination signal (INT3) of the command/image discrimination circuit 12 shown in FIG. 7 and image valve man 1 signal (INT4). There are four types. When these four types of signals are input, the interrupt controller 41
The CPU 40 outputs an interrupt signal lNTR to the CPU 40 and starts operating. 42 is based on address information on the address bus 60 output by the CPU 40.

This is an address decoder that accesses each part that is controlled by cr'u4o. 43 is a read-only memory (ROM) in which the operation control program of the CPU4Q is stored.
It is. 44 is a random access memory (RAM) having a storage space as shown in Table 1. 45 is the event timer 04 for detecting the loop break mentioned above.
Reference numeral 6 denotes an operation section of the terminal, and 47 indicates a key and display controller for controlling input/output of keys, display, etc. provided on the operation section 46, such as Intel's 8279.
It is. 47 and 48 are input/output ports (I10 ports), such as Intel 8255. The Iβ port 47 receives operation signals of five switches SW1 to SW5 provided in the command analysis and command generation circuit, and a signal 5IZJ from the printer device 16 indicating the size of the recording material set in the printer device. Eight signals are input: a signal POK indicating completion of operation preparation and a signal PEND indicating completion of operation of the printer device. The I10 port 48 receives a command signal CMDS that causes the command discrimination signal generation circuit 30 to generate a command discrimination signal, a signal PRED that instructs the printer to prepare for operation, and a printer activation request signal P8T, and 4.29 is shown in FIG. 27 is an input command register.

Table 1 1'LAM TABLE Master flag Channel grave line check flag Address 1 Number code area Line normal flag Address 2 Line abnormality flag Address 3 Destination (I register
Address 4 FiLL2 flag
Destination address code, FiLL3 flag
Original size repeat flag Received number of sheets area transmission request flag Maximum number of sheets area source flag Transmission command/packet reception source flag Reception command/packet reception completion flag Figures 9 to 13 show the command analysis and command generation circuit 2.
8 C! This is a control flowchart diagram of the PU 40, and the program is pre-stored in the ROM 43. Below 0, these 70-charts will be explained. Then, first, the above-mentioned loop disconnection detection is performed. Figure 9 shows power-on 70-. The terminal is powered on, and in step 70, the interrupt controller of Figure 8 is activated. 41, event timer 45, key and display controller 4
7. controller 47.48 and RAM'-44
After that, in step 71, the I10 controller 47 is read and bit 50 is initialized.
By determining whether the input is "1" or not, that is, by determining whether SW5 in FIG. 7 is activated, it is determined whether the terminal is a master terminal capable of issuing command packets at system startup. The input of 0 bit 5 which determines whether or not is rl
If J, the terminal is a master terminal, so set the master flag in RAM44; otherwise, set the master flag in RAM44.
Resetting the master flag of 0 then step 72
In step 73, set bits 1 to 4 of the controller 47 to the channel number area of the RAM 44. 0, that is, store the address of the terminal set in SW 1 to 4 in the RAM 44. Then, in step 73, set a predetermined timer value in the event timer 73. Set the timer and start the timer operation, and then
In step 74, it is determined whether or not the master flag is set in the RAM 44. If it is set, the output command register 29 is set to 0, which is an empty packet, and the master flag is set to 0. If not set, power on 70-
0 After this, if there is no broken part in the loop and it is normal, if it is a master terminal, the command packet issued by itself ends the loop by 1 before the event timer 45 times up.
It is input repeatedly. In addition, the command packet issued by the master terminal is input to terminals other than the master terminal before the time-out of the event-h timer 45. Therefore, when the loop is normal, the command discrimination signal INT3 is input to the interrupt controller 41, and this fact is also transmitted to the interrupt terminal of the 0PU 40, and the 0PU 40 operates.

However, if there is a break in the loop, the event timer 45 times up before the command packet is input. And the time-up signal lNT of the signal indicating this time-up
1 is input to the interrupt controller 41, and further 0PU4
This notification is sent to the 0 interrupt terminal, and the 0PU 40 operates.

Figures 10A to 1OJ are command discrimination signal interrupt routines when the command discrimination signal INT3 indicating that a command packet has been input to the terminal is input, and the routine in Figure 10A is used to detect loop breakage. Since the line check flag was set in step 73 of power-on 70- in FIG. 9, step 80
Then, the process proceeds to step 81. In step 81, since the loop 1 flag indicating that a command packet has already been input has not been set yet, the loop 1 flag is set. In step 82, the input command register 27
Loads the command packet input into the received command packet area of the RAM 44. In step 83, it is determined whether or not the command packet loaded into the RAM 44 is an empty packet. In this case, since it is an empty packet, the process proceeds to step 84 to determine whether the transmission request flag indicating that the terminal has a transmission request is set. 10 In this case, since there is no transmission request, the process proceeds to step 85, forms an empty packet in the transmission command packet area of the RAM 44, and loads it into the output command register 29 in step 86. Then, in step 87, the event timer 45
A predetermined timer value is set in , the timer operation is started, and the command discrimination signal interrupt routine is ended. Thereafter, when a command packet is input again before the event timer 45 times up, the command discrimination interrupt routine is started again. At this point, loop disconnection detection is completed and it is determined whether the loop is normal. At step 81, now RA
Since the loop 17 flag is set in M44, the loop 1 flag is reset, the line check flag is reset, the line normal flag is set, and the abnormal flag is reset. Then, the content of the received command packet loaded into the RAM 44 is analyzed again,
Furthermore, if no transmission request is input to the terminal, an empty packet is loaded into the output command register 29 and the timer operation of the event timer 45 is started again.

However, if the event timer 45 times up before the input of the command packet, the time-up signal lNT1 is input to the interrupt controller 41 and the timer interrupt routine of FIG. 11 is called. In step 5o, if loop breakage is not detected and the loop is normal according to the routine shown in FIG. finish.

However, if the line 7 rasog is not sent, it is determined that no command packet was input before time-up, a line abnormality flag is set in the RAM 44, and the process proceeds to step 51. In step 51, it is determined whether a master flag indicating that the terminal is a master terminal is set. If the terminal is the master and the master flag is set, an empty packet is set in the output command register 29 and the process proceeds to step 52; if the terminal is not the master, the process proceeds to step 52.0 At step 52, a predetermined timer value is set in the event timer 45. When the terminal is the master as described above, when the time-up occurs before inputting a command packet, it outputs an empty command packet again and at the same time starts the timer operation of the event timer 45. Also, the timer operation of the event timer 45 for the terminal line that is not the master is restarted.

In this way, how many times is the loop disconnection detection repeated? If a command packet is still not input normally even after performing the detection operation a predetermined number of times, it is determined that there is definitely a disconnection in the loop, and each terminal is In addition, since each terminal is configured to individually detect loop breakage, if there is a break in the loop, the location of the cut can be accurately determined. FIG. 12 shows a key-in interrupt routine when a key input signal INT2 indicating that a key of the operation unit 46 has been operated is input. The information input from the operation unit 46 is
There are four types: the destination of image information, the number of image information to be transmitted, the size of image information to be transmitted, and an instruction to start transmission. In step 90, the information of the key that has been terminated is stored in the RAM 44.
Store it in the corresponding area. If the destination address key is entered, enter the address code.
Set 0 in AM44. Also, if the transmission number key is entered, the RAM44 corresponding to the destination address.
Set the number of sheets in the number of sheets code area. Also, after the above three types of information for setting the size in the original size area are entered, and the transmission start key is entered, the R button will be pressed.
Check whether the number of sheets has been set in the area corresponding to the four sending addresses of AM44 in order from addresses 1 to 4. Also, set the number of sheets in the address bit of the first destination in the send command packet area, and then set the number of sheets to be sent to the number of sending bits. Set the number of sheets to the address bit and the number of transmission bits. ○Also, if a destination with a number of sheets set is confirmed, set the repeat flag in the RAM 44. 0 Also, if no further destination is confirmed, send more. Set the command's original size bit and destination address bit to 0, and set the send request flag of FLAM44. Here, RAM4
In the transmission command packet area 4, a transmission command packet that is to be output when an empty command packet is received is set. That is, a command packet based on the destination address, number of sheets to be transmitted, document size, etc. input from the operation unit 46 is formed in the transmission command packet area in the RAM 44. 74, FiLL27 rasog indicates that information regarding the terminals with addresses 1 and 2 has been set in the transmission command bat area in the RAM 44, and FiLL3 indicates that information regarding the terminals with addresses 1 and 3 or 2 has been set in this area.
This indicates that information regarding terminals 3 and 3 has been set.

When a command packet is thus formed in the transmission command packet area of the RAM 44 and an empty packet is input to a terminal whose transmission request flag is set, the command discrimination signal interrupt routine is called by the command discrimination signal INT3. Then, this terminal becomes the source of the image information and starts the protocol necessary for transmitting the image information to the destination.

The operation of the source terminal will be explained below.

Refer again to the command discrimination signal interrupt routine in Figures 10A to IOJ.0 As mentioned above, when a transmission command packet is formed in the transmission command packet area of the RAM 44 and an empty packet is input to the terminal where the transmission request flag is set. The routine of FIG. 10A is called by the command discrimination signal INT3. Since the 0 line check flag has already been reset, the process advances to step 82 and the command packet input to the command register is R.
Load into the AM44 received command packet. Then, in step 83, the content is determined and it is an empty packet, so the process goes to step 84 and checks whether the send request 7 rung is set. In this case, there is a send request, and the send request flag is set in the RAM 44-. Therefore, proceed to step 92. In step 92, send request 7 of RAM 44 and reset blowfish.
Furthermore, a source flag indicating that the terminal has become the source is stored in the RAM 44, and the process proceeds to step 86. In step 86, R
The command packet formed in the transmission command packet area of AM44 is loaded into the output register 29.

Then, at the same time as sending out the command packet, a predetermined copy is set in the event timer in step 87, the timer operation is started, and the routine of FIG. 10A is ended. At this point, a command packet with bits set indicating the destination, the corresponding number of transmissions, the source, the original size, and the line connection is transferred onto the loop. The source terminal then waits for this command packet to pass through all terminals and be input again.

When a command packet is input again to the source terminal, the routine shown in FIG. 10A is called by the command discrimination signal INT3. This command packet includes information regarding transmission and a response from the destination. Therefore, it is determined in step 82 that the command packet loaded into the RAM 44 is not an empty packet, and the process proceeds to step 88.
Since the source flag is set in the RAM 44, the process advances to [F] in FIG. And step 101
Check whether the reception ready bit, transmission start command bit, and transmission completion bit are set in the command packet in the reception command packet area of the RAM 44.0 In this case, these three types of bits are not set, so step Proceed to step 102 In step 102, it is determined whether or not the bits corresponding to the first and second destinations are set in the received command packet area.If they are set to 0, each bit is reset. Proceed to step 103, and if it is not set, set the number code area of the RAM 44 corresponding to the destination to O,
Furthermore, each response bit is reset and the process proceeds to step 103.In step 103, it is checked whether the repeat flag is set in the RAM 44 in the key-in interrupt routine of FIG. 12.If the repeat flag is set, further processing is performed. It is determined that there is a transmission destination for which the number of sheets has been set, and in step 104 it is checked whether the FiLL2 flag is set or not, and it is checked how many transmission destinations were set in the previous command packet.

That is, if the FiLL2 flag is set, it is determined in step 104 that the information to the destination corresponding to addresses 1 and 2 was set in the previous command, and whether the number of sheets is set in addresses 3 and 4 or not. See 0 In this case, if the number of sheets is set for both addresses 3 and 4, RA
Set address 3 in the first destination bit of the received command packet area in M44, and set the number of copies in the transmission count bit, set address 4 in the second destination bit, and set the number of copies in the transmission count bit. 0 Also, if the number of sheets is set for only one of addresses 3 and 4, that address is sent to the first address in the receive command packet area.
Step 106: Set the transmission destination bit to 0 and the number of sheets to the transmission count bit to 0. Then, reset the FiLL2 or FiLL3 flag and proceed to step 106.Step 106
Now reset the repeat flag and proceed to
44 is loaded into the command register 29, and the event timer 45 is activated. However, if the repeat flag is not set in step 103, the process proceeds to step 107.In step 107, it is checked whether or not the number of copies is set for destinations 1 to 4 in the RAM 44.0If it is the sender's terminal, the number of copies is set. has been completed, the process proceeds to step 108, and first the bit that inquires whether the receiving command packet is ready to be received is stored in the RAM.
44 is set to 0. Then, in step 109, it is sequentially determined whether or not the number of sheets is set in the area corresponding to each address.If the number of sheets is set to 0, the number of sheets is set to 0 in the area corresponding to each address. Figure 70-
The addresses are set in the first and second destination address bits of the received command packet area of the RAM 44 according to the chart. 1#I-If the number of sheets is set in three or more terminals, set the repeat flag.0 Then proceed to ■Load the received command packet set in the RAM 44 into the output command register 29, and start the event timer 45. In this way, the command packet with the bit set to inquire about the completion of reception preparation is output onto the loop. The source terminal then waits for this command packet to be input again as described above.

Next, when a command packet is input, the routine of FIG. 10A is called when the command discrimination signal INT3 is input, and if the reception ready bit of the received command packet is set, step 10 of No. 10CxyJ is called.
1 to [F] in Figure 10H. And step 1
If the destination response bit should have been set in step 01 but is not set, load the input received command packet into the output commander register 29 and return to step 3, where the command packet with the same content will be sent again. Output. If the destination response bit that should have been set is set, the response bit is reset in step 111, and it is determined in step 112 whether the repeat flag is set in the RAM 44. If not set, in step 113 the reception ready bit of the reception command packet is reset, and the transmission start command bit is set, and the process proceeds to Q in FIG. and step 105
Then, it is again sequentially determined whether or not the number of sheets is set in the area corresponding to each address in the RAM 44. Then, set the address in the receive command packet area, and
The program returns to and outputs the command packet set in the RAM 44. If the repeat flag is set in step 112, it is determined in step 114 whether the FiLL2 flag is set, and if it is set, the previous command packet is received by the destination corresponding to addresses 1 and 2. Assuming that the bit asking for completion of preparation is set and the response bit is obtained, address 3 is set in step 115.
Check whether the number of sheets is set to 4 or not. And R
, set the addresses in the address bits of the first and second destinations of the AM44 [7.Reset the repeat flag and return to ① Bit set command asking whether reception preparation is complete for the new destination set in the fiRAM44 Output the packet.

Next, when a command packet with the transmission start command bit set is input, the command discrimination signal INT3 causes the first
The routine shown in FIG. 0A is called and the process further advances from step 101 in FIG. 100 to [F] in FIG. 10I. In FIG. 10I, it is determined in step 116 whether the response bit for the transmission start command is set or not. If it is not set, the process returns to ■ and a command packet containing the same information is sent again. If the response bit is set, it is determined in step 117 whether the repeat flag is set. If it is set, ■ in Figure 10H
Proceed to. If it is not set, proceed to step 118, reset the transmission start command bit in the receive command packet area of the RAM 44, and further instruct the reader to start.
020 bit 3 is set. Then, among the set numbers corresponding to each destination address set in the RAM 44, the maximum number is set in the maximum number area of the RAM 44.

As described above, when a response from the destination to the transmission start command from the source is confirmed, the source terminal starts transmitting image information.

That is, an image packet formed by reading a document is output from the transmission source. When the image packet returns to the source end via each terminal, the image discrimination signal interrupt routine shown in FIG. 13 is called by the image discrimination signal INT4. If the terminal is the source, the process proceeds to step 120, where 1 is subtracted from the maximum number of images area, and when the content of the maximum number of images area becomes 0, it is assumed that the transmission of the image packet has ended, and the process proceeds to step 121.

Then l10 in step 121 to stop the league.
Reset bit 3 of 2, and set a bit in the receive command packet area to inquire about reception completion.

Then proceed to ■ in Figure 100. And step 105
Set the address of the terminal for which the number of sheets was set in the first destination or second destination bit of the received command packet.■
The command packet set in the RAM 44 is output. Also, if the value in the maximum number of images area does not become 0 in step 120, the image packet is output again. waits for a response pit from the destination. When the command packet is input, the command discrimination signal interrupt routine of FIG. 10A is called by the command discrimination signal INT3. Then, proceed to [F] in FIG. 10C. emanation
When a command packet in which a pit is set to ask the sender whether the reception is complete is input, it is determined in step 101 and the process proceeds to (2) in the first OJ diagram. In the flow chart of Figure 10J,
In step 122, it is determined whether or not the response bit for the reception completion pit is set, and if it is not set, the process returns to (2) and a command packet containing the same information is sent out again. If the response bit is set, the process advances to step 123 and it is determined whether the repeat flag is set. If it is set, the process advances to (2) in FIG. 10H and asks the destination of the remaining data whether the reception is complete. If it is not set, the process proceeds to step 124, where the transmit command packet is set to 0 and the process proceeds to (2) in FIG. 10A. At this point, all images have been sent from the source, and empty buckets are sequentially transferred onto the loop again.

Next, the operation of the destination terminal will be described.

Assume that the line check is completed, the source sends out a command packet containing information specifying the destination, and this command packet is input to a terminal other than the source. As a result, the command discrimination interrupt routine of FIG. 10A is called by the command discrimination signal INT3. In step 8o, since the line check and the clock have already been reset, the process proceeds to step 82, and the input command packet is loaded into the received command packet area of the RAM 44. The process then proceeds from step 83 to step 88, and since it is not the originator, the process further proceeds to step 89. Step 89
Then, it is checked whether the first destination address bit of the received command packet matches the channel number of the own terminal set in the RAM 44. If it matches, R, AM
The receiving source flag of 44 is set, and the process proceeds to (2) in FIG. 10B. If the bits do not match the first destination address bits, in step 90, the process checks to see if they match the second destination address bits, and if they do, proceed to the step shown in FIG. If they do not match, if it is not specified as either the first or second destination, the process proceeds to step 91, loads the received command packet as is into the output command register 29, and resets the receiving source flag in the RAM 44. Further, the process proceeds to step 87, where a predetermined timer value is set to the event timer, the timer is activated, and an empty packet is output. If the destination is specified as the first or second destination as described above, the process proceeds to step (2) in FIG. 10B. Steps 93 to 95 then determine what the received command packet is for.
Judgment is 0. In other words, if the first question is whether reception is ready, then
l10 reads the information and indicates whether printing is possible or not.
Check the signal of bit 7 of 1. If the 0 print operation is possible, proceed to O and check whether the receiving source flag is set in step 99. If it is set, it is assumed that your terminal is the first destination and the receive command number (first destination of Kerat) is sent.
Set the response bit of the destination (0) and load the transmitted command packet into the area.Also, if the receiving source flag is not set, assume that the own terminal is the second destination, and load the received command packet (the second Save destination response bits
)do. Then, l10 is a print operation preparation command.
Set bit 2 of 2 and set the specified number of transmissions to R.
, AM 44, and proceed to step 2 in FIG. 10A to output to the loop and start the timer.

However, if the printing operation is not possible, the process proceeds to O, and without setting the response bit of the 0 terminal, the process proceeds to 2 in FIG. 10A, where the received command is output.

Second, if the received command instructs the printer to start transmission, the printer device is made ready to receive the image signal in step 94, and the process proceeds to (2) to set the response bit.

Also, if the third question is to inquire about reception completion, step 95
Step 101 is read in step 101, and the signal at pit 8 of l101 indicating whether the printing operation is completed or not is checked. If the printing operation is completed, proceed to ◎ and set the response pit. If the printing operation has not been completed, proceed to ◎ and do not set the response pit. Also, if the received command packet does not ask any of the three questions mentioned above, read step 101 and set it in the printer device in step 97. It is determined whether Ilo 20 bit 6, which indicates the size of the recording material currently in use, is equal to the size specified by the received command packet. If they are equal, proceed to step 99 and set a response pit; if they are not equal, the response pit is set and a command packet is output.

In Figure 10B, a command packet with a response pit set for the transmission start command is sent, and when this command packet is confirmed by the sending terminal, the image packet is sent to the destination terminal. When the image discrimination signal INT4 is used, the 13th
The image discrimination signal interrupt routine shown in the figure is called.

In step 119, the source flag of the destination terminal is not set.

If the image packet corresponding to the set number of images has not been received, the reception completion flag is not set in the RAM 44, so 1 is subtracted from the received image number area of the RAM 44, and whether the number in the received image number area becomes 0 or not is determined. see what If it becomes 0, a reception completion flag is set in the RAM 44, and furthermore, pit 2 of l102, which is a signal output terminal for copying operation, is reset.

In this way, when the destination terminal inputs an image packet, it subtracts 1 from the reception number area of the RAM 44, and when that value becomes 0, it determines that the reception is complete, sets the reception completion flag in the RAM 44, and - image packet. Finish receiving. Then, a response pit is set for the next input reception command packet in which a pit is set inquiring about the completion of reception.

As explained above, according to the present invention, only one terminal that can output information packets on the loop is determined, and information collision on the loop can be prevented. Furthermore, the priority for the loop can be dynamically and automatically set using a simple configuration.

Although this embodiment describes a system in which four terminals are connected, the number is not limited to the number of terminals connected, and the terminals do not need to have both a recording function and a multi-function reading function. , or one with other functions such as a welfare display.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the connection of a loop transmission system using optical fibers to which the present invention is applied, Fig. 2 is a diagram showing the configuration of the image reading section 9, Fig. 3 is a diagram showing an image packet, and Fig.
5 is a diagram showing the contents of the command packet, FIG. 6 is a diagram showing the protocol procedure related to image transmission, FIG. 7 is a block diagram showing an example of the terminal circuit, and FIG. Figure 8 is a detailed circuit diagram of the command analysis and command generation circuit, Figures 9 to 13 are CPU control flowcharts, 12 is a command/image discrimination circuit, 27 is an input command register, and 28 is a command analysis circuit. 29 is an output command register, 40 is a CPU, 41 is an interrupt controller, and 43 is a ROM. 44 is a RAM. Applicant: Canon Co., Ltd. (Timer prisoner H-20?)

Claims (1)

[Scope of Claims] (1) A loop transmission system in which a plurality of image processing devices are connected in a loop through a signal transmission member, and image transmission is performed by sequentially transferring packetized information using the signal transmission member as a medium. 2. A loop transmission system according to claim 1, wherein the image processing device is configured to be capable of outputting the packet to the loop when the system is started. (2. In Claim 1, the loop transmission system is characterized in that the setting is performed by a selection member provided in each of the plurality of image processing apparatuses. (5) Claim 1 A loop transmission system characterized in that one of the above packets is present in the loop.