JPH10224425A - Serial communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system where a communication main station sends/ receives information of one communication unit or over to/from devices placed on a serial communication line. SOLUTION: The system is provided with a communication unit 203 having a CPU 222 that has a storage area in a plurality of communication information units designated respectively by specific addresses on a serial communication line 207 and sends/receives information of a storage area designated by address data sent from a main body controller (communication main station) serially on the serial communication line 207 for designation to an object storage area and communication units 203 are placed to optional positions on the serial communication line 207. The CPU 222 writes transmission desired data to a transmission area of the storage area and read data in the reception area and the main body controller sends/receives in a plurality of information units addressed by a plurality of addresses on the serial communication line 207.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a serial communication system, and more particularly to a technique for serially transmitting control information in an apparatus (for example, an electrophotographic image forming apparatus) including a plurality of control units.

[0002]

2. Description of the Related Art Conventionally, in order to realize a controlled and desired operation sequence, an apparatus composed of a plurality of control units transmits control information necessary for each other to one communication line for one binary physical event. Or transmit or receive a plurality of physical events as time-series binary data
This has been done by sending or receiving this over two communication lines.

FIG. 5 shows an example of a conventional electrophotographic image forming apparatus composed of a plurality of control units connected to each other by such a communication system. However, only some of the functional blocks necessary for the description of the present invention are representatively extracted, and do not explain the operation of the entire image forming apparatus.

In FIG. 5, reference numeral 1 denotes a main body of the apparatus, which includes a main body controller 7 for controlling an operation sequence of the entire apparatus. Reference numeral 2 denotes a document feeding unit (hereinafter, referred to as a feeder), which includes a feeder controller 8 for controlling the unit. 3 is an output paper sorting unit (hereinafter referred to as a sorter)
And a sorter controller 9 for controlling the unit is provided therein. Reference numeral 4 denotes a power supply unit which includes a power supply controller for controlling the unit. Reference numeral 5 represents one of the stepping motors used in the apparatus as a representative. Reference numeral 6 denotes a paper cassette.

Further, a large number of binary sensor units typified by so-called photo-interrupters and a large number of binary output units typified by solenoid, clutch and stepping motor drive pulses are arranged inside the apparatus. In this example, a part of them is taken for explanation.

[0006] Further, transfer papers (also referred to as recording paper, copy paper, copy paper, recording medium, etc.) of any size are set in cassettes 10, 11, 13 and 14 in upper and lower tiers. The switch unit is a size detection switch unit for detecting whether or not the size is changed, and outputs a state by binary output, and distinguishes four types of sizes by combination.

Reference numerals 12 and 15 denote transfer sheet detection units for detecting whether or not transfer sheets are present in the sheet feeding cassette 6. Reference numeral 16 denotes a solenoid unit for mechanically operating so as to apply pressure between the paper feed roller and the transfer paper so that the transfer paper set in the paper feed cassette 6 can be sucked up by the paper feed roller (not shown). is there. Reference numeral 17 denotes a clutch unit for applying a torque of a paper feed motor (not shown) to the paper feed solenoid.

Reference numeral 18 denotes a paper feed sensor for detecting a state in which the supplied transfer paper passes through the paper supply path, and reference numeral 19 denotes a state in which the supplied transfer paper passes through the transport path. Is a paper discharge sensor for detecting a state in which the paper after the copying operation has passed through the paper discharge path.

The main body controller 7 has a three-channel (channel) serial communication channel for transmitting control information in the apparatus. The feeder controller 8, the sorter controller 9, and the power supply controller 21 are for transmission and reception, respectively. Are connected by one cable.

The data format on each communication line is generally as shown in FIG. In other words, one communication unit (hereinafter,
A start bit (ST) indicating the beginning of the frame, an 8-bit (1 byte) data string (D0 to D7), and a parity bit (PA) indicating the sum of the 8-bit data, 1
Stop bits (SP) indicating the end of the information unit are transmitted in time series. Two units (for example, the controller 7
When it is necessary to transmit and receive a plurality of bytes of data between steps (8) and (8), this frame transmission is repeated a predetermined number of times, and the receiving side sequentially saves the byte data to a predetermined reception data storage area (not shown). Is performed.

Each of the binary sensor unit and the binary output unit is directly connected to an I / O port of a microcomputer inside the main body controller 7.
However, when the number of I / O ports of the microcomputer is smaller than the total number of the binary units, an I / O expansion device is interposed between the I / O ports and the binary units to output a plurality of binary outputs. The signal of the unit may be divided and connected to one I / O port of the microcomputer at an appropriate timing. Also in this case, from the viewpoint of the relation between the main body controller 7 and the external unit, the relation that each binary unit is connected one-to-one by a communication line (cable) dedicated to each is not changed.

In actuality, the photocoupler such as 18, 19 requires three cables of power supply +5 V, GND (ground, ground potential), and signal (Out) as shown in FIG.

As shown in FIG. 8, the solenoid 16, the clutch 17 and the like require two cables of a power supply +24 V and a signal (including a return signal). In addition, the four-phase stepping motor 5 requires a power supply of +24 V and five cables for each phase signal (including a return signal).

Each connection line in FIG. 5 shows the above-described connection form. In addition, a plurality of functional units transmit and receive necessary information to and from each other by the above-described connection form, control the entire apparatus, and realize a desired operation sequence.

However, in such a conventional example, a large number of binary sensor units and binary output units are individually connected to the main body controller unit, and if the power supply line and the GND line are included, the sensor unit has one bit per bit. Since three cables are required and two cables are required for each bit in the output unit, a considerable amount of cable bundles are drawn from the main controller.

In order to solve this problem, a binary sensor unit and a binary output unit are shown in FIG.
There has been proposed a serial communication system capable of cascade connection as shown in FIG. Reference numerals 33 and 34 in FIG. 9 denote communication devices. Each of the communication devices 33 and 34 includes one for each binary sensor unit or each binary output unit.
One or several of them are collectively prepared, and each is addressed by a unique address number. In this example, it is assumed that the communication device is capable of performing binary input or binary output of up to 8 bits without mixing input and output. Next, the operation of the serial communication system will be described.

The main body controller 7 serially sends the address on a communication line to communication devices 33 and 34 to which a binary sensor unit or a binary output unit to which data is to be transmitted / received is connected. This communication line logically communicates data to all communication devices at the same time, and each communication device monitors this address data all at once, and only the device that matches its own address responds thereto.

In the case of a binary sensor unit, the communication device 34 serially sends out the value of a binary sensor connected to its own data input port on a communication line. At this time, as shown in FIG. 9, when there is an unconnected one at the data input port of the communication device, the h level is transmitted to the communication line by the pull-up resistor.
The main controller 7 receives this data on the communication line and can read the value of the target binary sensor. on the other hand,
In the case of the binary output unit, the communication device 33 takes in the byte data sent from the main controller 7 following the address data, and outputs the received data in parallel to the output port.

With such a serial communication system, data of a number of binary sensor units and binary output units scattered in various places in the apparatus can be connected in cascade through one communication line, so that the data is extracted from the main controller. Cables will be greatly reduced.

[0020]

However, in the above-described conventional example, a large number of binary units (binary sensor units and binary output units) dispersed in the apparatus are connected to one.
Although it is possible to cascade through two serial communication lines and pick up or write out the data, in principle, the number of input ports or output ports assigned to one communication device and the number of communication devices cascaded There has been a problem to be solved in that it is only possible to transmit and receive multi-valued binary event data.

That is, in the case of serial communication in which an analog amount is exchanged by serial communication, one communication device is usually addressed by one address, and only one address data memory (for example, 8 bits) is provided. That was the conventional basic. However, then, one physical event such as A-D data
In the case where all the bits are occupied, one communication device is used by itself, and when controlling a normal binary system (coupler, solenoid, etc.), many There was a problem that a communication device became necessary.

An object of the present invention is to solve the above-mentioned problems by enabling a communication subject station to transmit and receive information of a communication device arranged on a serial communication line and information multiplied by one communication unit or more. To provide a serial communication system.

[0023]

In order to achieve the above object, the present invention is directed to an external device for inputting external binary data of one bit or a plurality of bits to one serial communication line in the same device. A plurality of child transmitting stations having binary data input means or a plurality of child receiving stations having external binary data output means for outputting the external binary data are connected in a cascade connection, and a unique identification number on the serial communication line is used. When the address data of the own station is sent out from the subject communication station onto the serial communication line, the slave transmitting station and the slave receiving station to be addressed respond to the address data of the own station. Serially outputting external binary input data on the serial communication line;
In the case of a slave receiving station, in a serial communication system that receives serial data from the serial communication line and outputs the external binary data, a plurality of communication information units each designated by a unique address on the serial communication line Storage means having a storage area of: and the communication subject station serially sends one address data of the unique address onto the serial communication line to designate a target storage area of the storage means. ,
A communication control unit for transmitting and receiving information of the storage area specified by the address data, comprising: a slave communication station, wherein the slave communication station is arranged at an arbitrary position on the serial communication line. I do.

Here, the communication control means may be a microcomputer for controlling the operation of the slave communication station, and the storage means may be a memory built in the microcomputer.

Further, the slave communication station is assigned a plurality of addresses corresponding to the respective storage areas for communication, and issues various digital and analog control signals based on information in the storage area specified by the address data. It may be a functional unit that communicates with the outside via the microcomputer and executes a predetermined control operation.

Further, the microcomputer can write desired transmission data in a transmission area of the storage means and can read data of a reception area of the storage means. , Data of a plurality of information units addressed by a plurality of addresses can be transmitted and received.

Further, when a signal having an analog amount, such as an output of a thermistor unit for detecting the operating environment of the apparatus, is input to an A / D conversion port of the microcomputer, the microcomputer is configured to output the analog signal amount. A / D-converts and writes the output value to a predetermined address in the storage area, and the communication subject station optimizes the operation sequence of the device according to the operation condition estimated from the analog signal amount. When the predetermined address is transmitted on the serial communication line in order to execute a control sequence, the slave communication station recognizes the address and serially transmits data of the predetermined address.
The communication subject station transmits the data, the communication subject station recognizes the analog signal amount from the received data, and selects an optimal control sequence according to the analog signal amount. The operating condition estimated from the analog signal amount is, for example, the environmental temperature of the device.

Further, the communication subject station main body determines in advance if it wants to transmit the control constant of the in-flight device controlled by the multi-level control data by the function of the slave communication station to the corresponding storage address of the slave communication station. The slave communication station recognizes the received address, receives the subsequent multi-bit control constant, transfers the received multi-bit control constant to the storage area, and transfers the multi-bit control constant to the storage area. The computer may read the data at the address and output an in-flight device control pulse width modulation signal corresponding to the value of the data from its own output port. The in-machine device is, for example, a cooling device, and the multi-bit is, for example, 8 bits.

Further, the communication subject station is a main body controller for controlling the entire operation sequence in the image forming apparatus including a plurality of various control units such as a feeder controller, a sorter controller, and a power supply controller and transmitting control information. It can be.

Further, the slave transmitting station may be a binary input unit for transmitting a binary input from a plurality of external binary data input means such as a photocoupler to the main controller.

Further, the slave receiving station is a binary output unit for outputting a binary output from the main body controller to the external binary data output means such as a solenoid, a clutch and a stepping motor. Can be.

Further, the apparatus may be an electrophotographic image forming apparatus.

According to the present invention, as described above, a child transmitting station including external binary data input means of one bit or plural bits or a child receiving station including external binary data output means is provided on one serial communication line. Cascade connection
When the slave station addressed by the unique ID transmits the address data of the own station on the serial communication line from the communication subject station, the transmitting station serially transmits its own external binary input data in the case of the transmitting station. In a serial communication system such as serial output on a line, receiving data from a serial communication line in the case of a receiving station, and external binary output, in a serial communication line, a plurality of addresses Since it has a storage unit including a storage area for a plurality of communication information units to be specified, and a slave communication station for transmitting and receiving information of a plurality of communication information units by a serialized address specification with a communication subject station, a serial communication line is provided. It becomes possible for the communication subject station to transmit and receive information that is equal to or greater than the number of multiplications of one communication unit with the communication device arranged above. .

[0034]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a circuit configuration of a communication system according to an embodiment of the present invention. In FIG. 1, reference numeral 201 denotes a sensor unit including a communication device 204 having a binary input port of 8 bits, as described in the above-described conventional example.
H (H: hexadecimal) address is assigned. The sensor unit 201 includes a serial communication line (also referred to as a serial communication data line) 207 and a + 5V power supply line 20.
8, the GND line 209 and the + 24V power supply line 210 are connected by the first connector 211 from the front stage, and are connected by the second connector 212 to the rear stage. A unit 202 described later,
203 also cascade-connects these lines. Note that the + 24V power supply is the sensor unit 201 in this example.
Is not used inside and is directly connected to the subsequent stage. The binary data line connected to the input port of the communication device 204 is connected to the + 5V power supply line and the GND line 209, and to the four photocouplers 214, 215, 216, and 217 via the third connector 213, respectively. Connected.

Reference numeral 202 denotes the same as described in the above conventional example.
An output unit comprising a communication device 205 comprising 8 bits of a binary output port, which is assigned an address of 02H. In the output unit 202, the upper 4 bits of the 8-bit data received from the serial communication line 207 are output from the output port of the communication device 205,
The third connector 218 is connected to a four-phase stepping motor 219 via a current driving element (eg, a transistor). For this motor 219, +
24V is also separately connected.

Reference numeral 203 denotes a functional unit including a communication device 206 which exhibits the features of the present invention.
Is allocated from 10H to 1FH as its address, and has a communication storage area (not shown) of 1 byte per address and a total of 16 bytes. The address area of the communication storage area is the same as that of the functional unit 203.
(CPU) 222 that governs the operation of
Are connected via an address bus 223, a data bus 224, and a control bus 225 for control signals, and are readable and writable from the microcomputer 222.

The microcomputer 222 has third and fourth microcomputers.
And various digital and analog control signals are transmitted / received to / from the outside via the connectors 220 and 221 to execute a desired (that is, instructed) control operation. In this example, an example in which one analog signal is input to an A / D conversion port (analog-digital conversion port) 226 of the microcomputer 222 is shown.

Next, the operation of the communication system of FIG. 1 will be described.

Sensor unit 201, output unit 20
2 has the same basic operation as the conventional example. When the main body controller (see 7 in FIG. 9) wants to check any value (detection value) of the photocouplers 214, 215, 216 and 217 connected to the sensor unit 201, the address is set on the serial communication line 207. 01H is transmitted serially. In this example, it is assumed that 32 addresses from 00H to 1FH are represented by 5-bit signals from A0 to A4.

Communication device 2 on sensor unit 201
04 detects this 01H and sets the input port PI_0 to P
The values up to I_7 are serially transmitted on the serial communication line 207. Since the photocouplers 214, 215, 216, and 217 are connected to the input ports PI_0 to PI_3, their values (detected values) are transmitted. Although ports PI_4 to PI_7 are not shown but are unused and released, the communication device 204
H (high level signal) by pull-up resistor inside
Is transmitted from these ports PI_4 to PI_7. This signal form is shown in FIG.

As shown in FIG. 2, in this example, an ST bit indicating the start of one frame, an SP beat indicating the end, and a PA bit indicating the sum total of data D0 to D7 are added. The main body controller receives the serial data from the data string in this format, and refers to the bit data corresponding to the input port to which the target photocoupler is connected. Input port PI_0 to P
The order in which the data up to I_7 is transmitted in chronological order is merely a matter of communication specifications, and it is possible to freely determine the order in any order. In this example, PI_0, PI_1,... Are sequentially transmitted in order to simplify the description.

When the main body controller wants to drive the stepping motor 219, the serial communication line 20
7, the address 02H is transmitted. Following this address transmission, the main controller sends the stepping motor 21
9, a data string for outputting a pulse signal to each phase of A, * A (inverted A), B, * B (inverted B) from the corresponding output port. In this example, the output ports PO_0,
Considering that A, B, * A, and * B shown in FIG. 3 correspond to PO_1, PO_2, and PO_3, respectively, and that an output transistor is interposed, a data signal sequence on the serial communication line 207 is considered. Will be repeated as shown in FIG.

Next, the functional unit 2 which is a feature of the present invention is described.
03 will be described. The operation of the functional unit 203 is controlled by the microcomputer 222, whereby desired operations and functions are realized. The communication device 206, which is a feature of this example, is connected to the microcomputer 222 by a bus, and releases a transmission data storage area (not shown) and a reception data storage area (not shown) therein to the microcomputer 222.

That is, the microcomputer 222 can write desired transmission desired data in the transmission area of the communication device 206 and read data in the reception area. Therefore, for example, by defining the contents of each of the transmission and reception storage areas of the communication device 206 (not shown), the main body controller can control a plurality of addresses addressed by a plurality of addresses on the serial communication line 207 as described above. It is possible to transmit and receive data in information units.

For example, it is assumed that the output of a thermistor unit (not shown) for detecting the operating environment of the apparatus is now input to the A / D conversion port 226 of the microcomputer 222. The microcomputer 222 performs A / D conversion of the output value of the thermistor unit, and writes the output value to an arbitrary predetermined address, for example, 10H. The main body controller sends an address 10H to the serial communication line 207 to execute a control sequence that optimizes the operation sequence of the device according to the environmental temperature of the device. The communication device 206 recognizes this address, and
H data is transmitted serially and transmitted to the main controller. The main body controller receives the data, recognizes the environmental temperature of the apparatus from the received data, and selects an optimal control sequence according to the environmental temperature.

If the main body controller wants to transmit the control constant of the internal cooling device controlled by the functional unit 203 to the corresponding storage address of the communication device 206, for example, the main body controller sets a predetermined arbitrary address such as 20.
H, followed by serial transmission of the 8-bit control constant. The communication device 206 receives the address 2
It recognizes 0H, receives the next 1-byte data (8-bit control constant), and transfers it to the internal storage area. The microcomputer 222 of the functional unit 203 reads the data at the address 20H, and outputs a cooling device control PWM (pulse width modulation) signal corresponding to the value of the data from its own output port 227.

(Other Embodiments) In the above embodiment, a copying apparatus has been described as an example. However, the present invention is not limited to this, and can be applied to a case where one apparatus or system includes a plurality of control units.

Further, the present invention may be applied to a system constituted by a plurality of devices or to an apparatus constituted by a single device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus. In this case, by reading a storage medium storing a program represented by software for achieving the present invention into the system or the apparatus, the system or the apparatus can enjoy the effects of the present invention. Becomes

[0050]

As described above, according to the present invention,
Since a slave station having a plurality of addresses is considered even though it is one communication device, a device having many control targets in a coverage area is realized. More specifically, in the present invention, 1
A child transmitting station (communication device 204) including external binary data input means consisting of one or more bits, or a child receiving station (communication device 2) including external binary data output means
05) on one serial communication line (207), and those slave stations addressed by a unique ID (identifier: address) receive their own address data serially from the communication main station (main controller 7). When transmitted on the communication line, in response to the data transmission, the slave transmitting station (204) serially outputs its own external binary input data on a serial communication line, and the slave receiving station (205) In a serial communication system that receives serial data from a serial communication line and outputs external binary data, a plurality of transmission / reception data storage areas addressed by a plurality of addresses can be stored in one communication device (206) and one serial communication line (207). ) Arranged on a serial communication line because it is arranged at an arbitrary point on Effect that the communication device and a communication partner station over more than the number of information of the communication unit is capable of transmitting and receiving that is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a communication system according to an embodiment of the present invention.

FIG. 2 is a format diagram illustrating an example of a communication format according to an embodiment of the present invention.

FIG. 3 is a timing chart showing an example of a drive pulse of a stepping motor according to one embodiment of the present invention.

FIG. 4 is a diagram illustrating an example of transmission data of a driving pulse of a stepping motor according to an embodiment of the present invention.

FIG. 5 is a schematic diagram showing an internal configuration of a conventional device.

FIG. 6 is a format diagram showing a communication format example of a conventional example.

FIG. 7 is a diagram showing a configuration example of a conventional binary sensor unit.

FIG. 8 is a diagram illustrating a configuration example of a conventional binary output unit.

FIG. 9 is a block diagram showing a configuration of a communication system of a conventional example.

[Explanation of symbols]

 7 Body controller 201 Sensor unit 202 Output unit 203 Function unit 204, 205, 206 Communication device 207 Serial communication line 208 + 5V power line 209 GND line 210 + 24V power line 211, 212, 213 Connector 214, 215, 216, 217 Photocoupler 218 Connector 219 Stepping motor 220, 221 Connector 222 Microcomputer 223 Address bus 224 Data bus 225 Control bus 226 A / D conversion port 227 Output port of microcomputer

Claims (10)

[Claims] 1. A slave transmitting station having external binary data input means for inputting external binary data of one bit or plural bits on one serial communication line in the same device, or A plurality of slave receiving stations having external binary data output means for outputting are connected by cascade connection, and the slave transmitting stations and slave receiving stations addressed by the unique identification numbers on the serial communication line are automatically transmitted from the main communication station. When the address data of the station is transmitted on the serial communication line, according to the address data of the own station, in the case of the child transmitting station, its own external binary input data is serially output on the serial communication line, In the case of a station, in a serial communication system that receives serial data from the serial communication line and outputs the external binary data, Storage means having a storage area for a plurality of communication information units each designated by a unique address on the serial communication line; and the communication subject station serially stores one address data of the unique address on the serial communication line. A slave communication station having communication control means for transmitting and receiving information of the storage area specified by the address data when the target storage area of the storage means is designated by sending the data; A serial communication system wherein a slave communication station is arranged at an arbitrary position on the serial communication line. 2. The serial communication device according to claim 1, wherein said communication control means is a microcomputer for controlling operation of said slave communication station, and said storage means is a memory built in said microcomputer. Communications system. 3. The slave communication station is assigned a plurality of addresses corresponding to each of the storage areas for communication, and transmits various digital and analog control signals based on information in the storage area specified by the address data. 3. The serial communication system according to claim 2, wherein the serial communication system is a functional unit that performs a predetermined control operation by communicating with the outside via the microcomputer. 4. The microcomputer can write desired transmission data in a transmission area of the storage means, and can read data of a reception area of the storage means, and the communication subject station operates on the serial communication line. ,
4. The serial communication system according to claim 2, wherein data of a plurality of information units addressed by a plurality of addresses are transmitted and received. 5. When an analog signal such as an output of a thermistor unit for detecting the operating environment of the apparatus is input to an A / D conversion port of the microcomputer, the microcomputer controls the analog signal amount. A / D-converts and writes the output value to a predetermined address in the storage area, and the communication subject station optimizes the operation sequence of the device according to the operation condition estimated from the analog signal amount. When the predetermined address is transmitted on the serial communication line in order to execute a simple control sequence, the slave communication station recognizes the address, serially transmits data of the predetermined address, and communicates with the communication subject station. The communication subject station receives the data, recognizes the analog signal amount from the received data, and receives the analog signal amount. Serial communication system according to claim 4, characterized in that to select the optimal control sequence in response. 6. The communication subject station main body determines a control constant of an in-flight device controlled by multi-level control data by a function of the slave communication station to a corresponding storage address of the slave communication station. The slave communication station recognizes the received address, receives the subsequent multi-bit control constant, transfers it to the storage area, transfers the multi-bit control constant to the storage area, 5. The serial communication system according to claim 4, wherein the computer reads the data of the address and outputs an in-flight device control pulse width modulation signal according to the value of the data from its own output port. 7. The communication subject station is a main body controller for controlling an entire operation sequence in the image forming apparatus including a plurality of various control units such as a feeder controller, a sorter controller, and a power supply controller and transmitting control information. The serial communication system according to any one of claims 1 to 3, wherein: 8. The secondary transmitting station is a binary input unit for transmitting binary input from a plurality of external binary data input means such as a photocoupler to the main controller. 8. The serial communication system according to 7. 9. The slave receiving station is a binary output unit that outputs a binary output from the main body controller to the external binary data output means such as a solenoid, a clutch, and a stepping motor. The serial communication system according to claim 7 or 8, wherein 10. The serial communication system according to claim 1, wherein the apparatus is an electrophotographic image forming apparatus.