JPS6295046A - Multiplex transmission equipment - Google Patents

Abstract

PURPOSE:To execute data transmission to each secondary station by only a transmission line of two cores, by constituting the titled device so that a primary station gives each intrinsic parameter to each secondary station, the secondary station calculates and holds this parameter, and at the time of the data transmission, data signal are counted and compared with holding value, and the data transmission is executed. CONSTITUTION:When a start signal is applied to a primary station 1 from the outside, a polling signal P1 is sent out of a polling signal transmitting circuit 11 and a counter 12 is brought to an increment, and a parameter A1 to a secondary station 2 is sent out. Each secondary station 2 calculates an arithmetic value by an operation holding circuit 27, and holds it in the operation holding circuit 27. When setting of the arithmetic value to all secondary stations 2-6 has been ended, the secondary station 6 of the last order applies a polling signal P6 to the primary station 1 through a transmission line 7. Subsequently, when a data transmitting/receiving operation is started, the primary station 1 transmits a data signal T1 to the secondary station 2 of the first order. The secondary station 2 discriminates by a comparator 29 whether the arithmetic value which has been held in the operating holding circuit 27 of the secondary station 2 is equal to a counting value of a receiving counter 28 or not, and outputs the receiving data T1 to the outside.

Description

[Detailed Description of the Invention] [Field of the Invention] The present invention relates to a multiplex system configured by connecting a primary station (master station) and a plurality of secondary stations (slave stations) in a digital chain manner using dedicated two-core wires. This relates to a transmission device.

[Summary of the invention]

The multiplex transmission device according to the present invention includes a primary station that sends parameters to each secondary station in advance and then sends a reset signal, and then sequentially transmits data with the secondary stations, The parameters given by the primary station are calculated using a predetermined calculation formula, the received data is counted, and the counted value is compared with the calculated value, and when they match, the data is transmitted to the primary station. A multiplex transmission device is constructed by a secondary station that performs Such a configuration makes it possible to perform data transmission in a short time without using addresses for each secondary station.

[Prior art and its problems] In general, in multiplex transmission equipment that configures a data transmission system by connecting a primary station and a plurality of secondary stations using a two-core dedicated line, any arbitrary number on a common lotus In many cases, a multi-drop method is used in which a secondary station is connected to the
It is necessary to set a unique address for each next station. Such address settings are usually done using the DIP installed at each secondary station.
It is set by a switch etc.

However, when it is necessary to make the secondary station extremely compact, there is a problem in that the DIP switch limits the miniaturization. Furthermore, when setting up a large number of secondary stations at once, setting addresses is relatively easy, but when increasing or decreasing the number of secondary stations after configuring the multiplex transmission equipment system, the addresses may not be consecutive. Furthermore, there is a possibility that a plurality of secondary stations may be set to the same address by mistake, resulting in a transmission error. In addition, a shift register method is known in which addresses are not specified for each secondary station in order to facilitate work at the site where secondary stations are installed, but this method requires a signal line for clock signals in addition to data signals. Therefore, a transmission system cannot be constructed using inexpensive two-core wires, and there is a problem in that the price of the transmission cable increases. Also, when setting a unique address for each secondary station and transmitting data using that address, the number of secondary stations is large (if the number of data to be transmitted is small, it takes time to transmit the address, so data transmission is slow). There was a problem in that the efficiency of the method decreased.

[Purpose of the invention]

The present invention has been made in view of the problems of the conventional multiplex transmission device, and uses DIP switches to
There is no need to set an address for the next station, and there is no need to add an address for each secondary station in the transmission data.
It is an object of the present invention to provide a multiplex transmission device that can perform data transmission with a large number of secondary stations in a short time.

[Structure and effects of the invention]

The present invention is a multiplex transmission device in which a primary station and a plurality of secondary stations are connected in a digital chain loop via a transmission line, and the primary station transmits predetermined parameters to each secondary station in sequence. a transmitting means; a polling signal transmitting means for transmitting a polling signal to the highest priority secondary station when setting an address;
It has a reset signal transmission means for sending a reset signal to each secondary station, and a data transmission means for transmitting data to each secondary station at predetermined intervals starting from the highest priority secondary station, and each secondary station filter means connected between the input and output terminals to pass the data signal and the reset signal and block the polling signal;
calculation holding means for receiving parameters given from the primary station after receiving a polling signal given from the primary station or an upper secondary station, and holding a value calculated by a predetermined calculation formula; a reception counter that counts the number of data received, a data signal reception means that receives a data signal given from the next station, a data signal transmission means that sends the data signal to the primary station, and a count value and calculation of the reception counter. The present invention is characterized by comprising a comparing means for comparing the calculated values of the holding means and providing a coincidence signal to the data signal receiving means and the data signal transmitting means when they match.

According to the present invention having such features, the primary station transmits the polling signal and parameters via the transmission line, and
Unique parameters are given to each subsequent station. The secondary station calculates and holds this parameter using a predetermined arithmetic expression, and thereafter, when transmitting data to any primary station, data is transmitted with the primary station by counting the data signal and comparing it with the held value.

Such a configuration makes it possible to transmit data to each secondary station using only two-core transmission lines.

Also, since addresses are not set for each secondary station, DIR
There is no need to provide a switch, the secondary station can be made smaller, and workability when installing the secondary station can be improved. Furthermore, since no address is added to the transmitted data, the transmission time for one cycle of data transmission with each secondary station can be shortened. In particular, when the number of secondary stations connected is large and the information f of transmission data between the secondary stations and the primary station is small, high-speed data transmission can be performed.

[Explanation of Examples]

FIG. 1 is a schematic block diagram showing an embodiment of a multiplex transmission apparatus according to the present invention. In this figure, primary station 1 and multiple 2
The next stations 2 to 6 are loop-connected in a digital chain by a two-core transmission line 7. That is, the output terminal 1-0 of the primary station is connected to the input terminal 2-i of the secondary station 2 connected to the highest order, and the output terminal 2-o of the secondary station 2 is connected to the next-order station by the transmission line 7. It is connected to the input terminal 3-4 of the secondary station 3. Similarly, the output terminals of the secondary station 3 and secondary stations 4 and 5 (not shown) are connected to the input terminals of the secondary stations 4 to 6 at the next stage, respectively. Then, the output terminal 6- of the secondary station 6 connected to the last rank
o is connected to the input terminal 1-i of the primary station 1 via the transmission line 7. The primary station 1 transmits parameters, reset signals, and transmission data to each secondary station connected in a loop, and performs data transmission with the secondary stations 2 to 6 at predetermined time intervals.

(Configuration of the primary station) As shown in FIG. 2, the primary station 1 has a polling signal transmitting circuit 11 that operates based on an external start signal and a counter 12 that is reset by the polling signal transmitting circuit 11. There is. When the polling signal transmitting circuit 11 is given a start signal, it transmits a polling signal modulated at, for example, a frequency of IMHz to the secondary station 2 connected in the highest order, and then sends a start signal to the parameter transmitting circuit 13. give a signal. The parameter transmission circuit 13 transmits parameters corresponding to the count value of the counter 12 to each secondary station 2 to
6, and also gives a counting input to the counter 12, and after sending out all the parameters, the reset signal sending circuit 14
gives an operation start signal to

The reset signal transmitting circuit 14 transmits a reset signal having a frequency of IMHz or less, for example, 60 KHz at the start of one cycle of each data transmission, and thereafter provides an operation start signal to the data signal transmitting/receiving circuit 15. The data signal transmitting/receiving circuit 15 has input and output terminals connected to the output terminal 1-o and the input terminal 1-i, respectively, and receives data signals from each secondary station and sequentially sends data signals to each secondary station. A counting input is given to the counter 12 every time a data signal is transmitted or received. The counter 12 performs an amplifier count of the count input, and provides the count value to the parameter transmission circuit 13, the comparator 16, and the count buffer 17. Also, input terminal 1- of primary station 1
A polling signal receiving circuit 18 is connected to i. The polling signal receiving circuit I8 gives a set signal to the count buffer 17, stops the transmission of subsequent parameters from the parameter transmitting circuit 13, gives timing for sending a reset signal to the reset signal transmitting circuit 14, and further resets the counter 12. It is something. The count buffer 17 is the counter 1 when the cent signal is given.
The count value of 2, ie, the number of connected secondary stations, is held and the data is provided to the comparator 16. Comparator 16
If the counted value of the counter 12 matches the number of secondary stations held, the operation of the parameter transmitting circuit 13 is stopped and a retransmission output is given to the reset signal transmitting circuit 14.

(Configuration of Secondary Station) FIG. 3 is a block diagram showing the configuration of the secondary station 2, and the other secondary stations 3 to 6 have similar configurations. Now, a low-pass filter 21 is connected to the input terminal 2-i of the secondary station 2.
and polling signal receiving circuit 22, parameter receiving circuit 2
3, a reset signal receiving circuit 24, and a data signal receiving circuit 25 are connected. The low-pass filter 21 is L C
A passive filter consisting of a passive filter that blocks a signal with a frequency of IMHz used as a polling signal regardless of the power supply state, and passes a data signal modulated at a frequency of IMHz or less, for example 60KHz sent from the transmission line 7, as it is. This signal is transmitted to the output terminal 2-o. The polling signal receiving circuit 22 receives the polling signal given via the transmission line 7, and transmits the polling signal transmitting circuit 2.
6, and also provides a set signal to the parameter receiving circuit 23 and the calculation holding circuit 27. Further, the data signal receiving circuit 25 provides a count input to the reception counter 28 every time a data signal is received, and outputs the received data signal to the outside when an enable signal is provided from the comparator 29. The data held by the arithmetic holding circuit 27 and the count value of the reception counter 28 are provided to a comparator 29. The comparator 29 determines whether these data match or not. If they match, it provides an enable signal to the data signal receiving circuit 25, and simultaneously stops the counting of the receiving counter 28 and starts the data signal transmitting circuit. 3
This gives the transmission timing to 0. The data signal transmitting circuit 30 has an output end connected to the terminal 2-o, and transmits input data onto the transmission line 7.

(Operation of this embodiment) Next, the operation of this embodiment will be explained with reference to a flowchart and time chart 1-. 4 and 5 are flowcharts showing the operations of the primary station 1 and each of the secondary stations 2 to 6, respectively. FIG. 6 is the initial parameter setting process, and FIG. 7 is the sending of each station during data transmission. It is a time chart showing signals. First, when a start signal is given to the primary station l from the outside, it starts operating, and in steps 41 and 42, the counter 12 is cleared and the polling signal transmitting circuit 11
The polling signal P1 is then sent out as shown in FIG. 6(a). Then, in steps 43 and 44, after the polling signal is sent, the counter 12 is incremented, and the parameter A(1) to the secondary station 2 is sent. After starting the operation, each secondary station 2 waits for a polling signal in step 61. When the secondary station 2 receives the polling signal P1, it proceeds to step 62 and receives the parameter A (nl) from the parameter receiving circuit 23. The data is given to the calculation holding circuit 27, and the calculation value is calculated using the following equation.

Calculated value=A(n)x2-1 (n=1 to 5) Which calculated value is held by the calculation holding circuit 27. Here, assuming that the parameter A(n) sent from the primary station 1 is equal to the count value n of the counter 12, the secondary station 2 holds 1 as the calculated value.

Next, proceeding to step 63, the polling signal transmitting circuit 2
6, a polling signal P2 is sent to the secondary station 3 as shown in FIG. 6 fb). If the primary station 1 does not receive a polling signal after transmitting the parameters in step 45, it returns to step 43 after a predetermined period of time, increments the counter 12, and then transmits the parameter A(21(~2).Secondary station 3 The receiving stage of the polling signal P2 performs similar processing and holds the above calculated value, in this case 3, in the calculation holding circuit 27.Then, the calculated values 5 and 7.9 are calculated for the secondary stations 4 to 6, respectively. After setting the calculated values for all secondary stations 2 to 6, the last secondary station 6 sends the polling signal P6 to the transmission line 7.
to the primary station 1 via. When the primary station 1 receives the polling signal P6 by the polling signal receiving circuit 18,
Proceeding to step 46, the count value of the counter 12 is set in the counter counter 17, transmission of parameters is stopped, and the parameter setting process is ended. Then, the count has the number of connected next stations, 5 in this case.
will be retained.

Next, when the data transmission/reception operation is started, the primary station 1 proceeds from step 47 to step 48, resets the counter 12, and sends out a reset signal R from the reset signal transmission circuit 14 as shown in FIG. 7 (al).Reset signal The frequency of R is sufficiently lower than the polling signal, and the reset signal is passed through the low-pass filter 21 of each secondary station and received by the reset signal receiving circuit 24 of all secondary stations 2 to 6, and the reception counter 28 is reset. (Steps 64.65).1
The next station 1 proceeds to step 50, increments the counter 12, and then transmits the data signal T1 to the highest ranking secondary station 2 (step 51). The secondary station 2 then receives the data signal and increments the reception counter 28 in step 66. Then, the comparator 29 determines whether the calculated value held in the calculation holding circuit 27 of the secondary station 2 is equal to the count value of the reception counter 28, in this case l. In secondary station 2, this value is the same and in all the other secondary stations 3 to 5, this value does not match, so only secondary station 2 proceeds to step 69.70 and transmits the data signal as shown in FIG. 7 (bl). R1 is sent to the primary station, an enable signal is given to the data signal receiving circuit 25, and the received data T1 is outputted to the outside.On the other hand, the other secondary stations perform step 6.
6 and waits for the next data signal. Now, the primary station 1 receives the data signal R1 from the secondary station 2.Step 52
), the process proceeds to step 53 to check whether the counted value of the counter 12 is equal to the number of secondary stations held in the counter \sofa 17. If these values are not equal, the process returns to step 50, the counter 12 is incremented, and the same process is repeated.Then, the secondary station 3 sends the data signal T2 to the secondary station 3.62 The secondary station 3 receives the data signal Tl.

Since R1 and T2 are sent onto the transmission line 7, the number of data is counted by the reception counter 28, and the data T
If 2 is sent out, it is equal to the calculated value (-3) in the calculation holding circuit 27 in the secondary station 3, so only the secondary station 3 goes to step 69.
．． Proceeding to 70, the data signal R2 is transmitted and the received data T
2 is output to the outside, and the other secondary stations 2 and 4.5 return to the steering knob 66 and wait for the next data signal. This will result in Figure 7(a).

(As shown in C1, only the secondary station 3 can perform data transmission with the primary station 1. Thereafter, the number of data signals sent out on the transmission line 7 in the same way for the secondary station 4.5 is counted by the reception counter, and only when the counted value and the held calculated value match, the received data signal T3~
T5 is output to the outside and data signals R3,
Send R4 and R5 respectively. In this way, data transmission can be performed between the primary station 1 and a plurality of secondary stations without setting an address for each secondary station.

In this embodiment, a multiplex transmission apparatus using five secondary stations has been described, but it goes without saying that a similar system can be constructed using an even larger number of secondary stations. Further, in this embodiment, a low-pass filter is provided in each secondary station to pass the data signal as it is and cut off only the polling signal, but a band cutoff filter that cuts off only the frequency of the polling signal may be used. Also, by using a low frequency signal as a polling signal and modulating the data signal and reset signal at a higher frequency than the polling signal,
It is also possible to configure the filter of each secondary station using a bypass filter that blocks only the polling frequency.

Furthermore, in this embodiment, a multiplex transmission device that alternately transmits data between each secondary station and a primary station has been described. The multiplex transmission device according to the present invention can also be applied when any of these secondary stations are connected by changing the calculation formula of the calculation holding circuit that calculates the number of data sent onto the transmission line during data transmission. It is possible to apply

Furthermore, without connecting the output terminal of the secondary station in the last order to the input terminal of the primary station in a loop manner, connect the end station to the secondary station in the last order to receive a polling signal (if received, It is also possible to connect in a digital chain type by sending the end signal back to the primary station.In this case, it is possible to connect in a straight line rather than in a loop, so it is possible to shorten the transmission line. .

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing an embodiment of the multiplex transmission device according to the present invention, FIG. 2 is a block diagram showing the configuration of the primary station 1 of the multiplex transmission device according to the present embodiment, and FIG. 3 is the present embodiment. A block diagram showing the configuration of the secondary station, Fig. 4 is the primary station,
Figure 5 is a flowchart showing the operation of each secondary station, Figure 6 is a time chart showing the output of each station during initial operation when setting parameters for each secondary station, and Figure 7 is during normal data transmission. 3 is a time chart showing the output of each station. i-1111--Primary station 2-6-----Secondary station 7...-Transmission line 11.26------
・Polling signal transmission circuit 12--Counter 13--Parameter transmission circuit 14--
---Reset signal transmission circuit L5--Data request transmission/reception circuit 16.29---Comparator 1
7-------Count buffer 21...-11-11 low-pass filter 23--Song parameter receiving circuit 25--Data signal receiving circuit 27--
1---Calculation holding circuit 28---Receiving counter
30... Data signal transmission circuit patent applicant Tateishi Electric Co., Ltd. agent Patent attorney Yoshiki Okamoto (and one other person)
Figure 5

Claims (2)

[Claims] (1) A multiplex transmission device in which a primary station and a plurality of secondary stations are loop-connected in a digital chain manner via a transmission line, and the primary station sequentially transmits predetermined parameters to each secondary station. a parameter transmitting means; a polling signal transmitting means for transmitting a polling signal to the highest ranked secondary station when setting an address; a reset signal transmitting means for transmitting a reset signal to each secondary station; and a highest ranked secondary station. Each secondary station has a data transmission means for sequentially transmitting data to each secondary station at predetermined intervals, and each secondary station has a filter connected between the input and output terminals to pass the data signal and the reset signal and block the polling signal. means, a calculation holding means for receiving parameters given from the primary station after receiving a polling signal given from the primary station or an upper secondary station, and holding a value calculated by a predetermined calculation formula; a reception counter that counts the number of data transmitted on the line; a data signal reception means that receives a data signal provided from the primary station; a data signal transmission means that transmits the data signal to the primary station; Multiplex transmission characterized by comprising a comparison means for comparing the counted value of the counter and the calculated value of the calculation holding means and providing a matching signal to the data signal receiving means and the data signal transmitting means when they match. Device. (2) The polling signal sent by the polling signal sending means of the primary station and each of the secondary stations is a signal having a higher frequency than the data signal and the reset signal, and the filter means of each of the secondary stations transmits the polling signal. 2. The multiplex transmission device according to claim 1, wherein the multiplex transmission device is a low-pass filter that blocks signals and passes data signals and reset signals.