JPH0720295B2 - Time division multiplex transmission system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a case where a master unit and a plurality of terminals are connected by a pair of signal lines, and the master unit accesses the terminals to transmit and receive data. The present invention relates to a division multiplexing transmission system.

[Prior Art] Conventionally, in this type of time division multiplex transmission system, as shown in FIG. 6, a master unit 1 and terminals 2a, 2b for monitoring a plurality of sensors, monitoring a switch, and controlling a load are used. , 2c are connected by a pair of signal lines 3, and a transmission signal Vs for individually accessing each terminal device 2 from the master device 1 to transmit and receive data is constantly transmitted, and at the same time, a sensor output is output to output a master signal. The signal processing of the sensor monitoring terminal 2a for returning data to 1 is performed in a signal processing cycle synchronized with a specific pulse (for example, start pulse) of each transmission signal Vs. FIG. 7 shows an example of the transmission signal Vs sent from the base unit 1 to the signal line 3,
Start pulse ST indicating signal transmission start, transmission mode data MD, address data AD for calling terminals 2a, 2b, 2c, control data CD for controlling load, response data setting pulse WT for monitoring data is bipolar (± 24V) Of the current mode signal obtained by connecting a low impedance between the signal lines 3 and the monitoring data returned to the reply band WT. It is configured to be returned by the return signal V _B.

[Problems to be Solved by the Invention] However, in the above-described conventional example, as shown in FIG. 8, when a predetermined number of bit data is transmitted / received by the transmission signal Vs, a constant cycle is generated. Although the signal processing of the sensor output is performed by the transmission signal Vs in the short message transmission mode for transmitting and receiving a predetermined number of bit data and the transmission in the long message transmission mode for transmitting and receiving a large number of bit data as shown in FIG. When the signal Vs and the master unit 1 are transmitted, that is, when the monitoring data returned from the switch monitoring terminal 2b or the control data transmitted to the load controlling terminal 2b has a variable length, the sensor output However, there is a problem in that the signal processing cycle may become longer and false alarm may occur. In the figure, the signal processing timing is indicated by a quadrangular perspective.

The present invention has been made in view of the above points, and an object thereof is to provide a sensor with a substantially constant cycle even when a transmission signal in a short message transmission mode or a long message transmission mode is transmitted. An object of the present invention is to provide a time-division multiplex transmission system that can perform output signal processing and does not cause false alarms.

[Means for Solving the Problems] A time division multiplex transmission system according to the present invention includes a master unit and a plurality of monitoring units,
The control terminal is connected with a pair of signal lines to constantly transmit a transmission signal that accesses each terminal from the master to send and receive data, and also processes the sensor output signal and returns the data to the master. In the time division multiplex transmission system in which the signal processing of the sensor monitoring terminal device is performed at the signal processing cycle synchronized with the specific pulse of each transmission signal, a short message transmission mode for transmitting and receiving a predetermined number of bit data and a large number of bits In addition to transmitting the mode data that sets the short message transmission mode for transmitting and receiving data with the above transmission signal, the mode determination unit provided in the sensor monitoring terminal device determines the transmission mode, and transmits the short message transmission mode. When a signal is received, signal processing is performed at the above signal processing cycle, and when a transmission signal in long message transmission mode is received, it is set by the internal timer. In the serial signal processing period substantially the same period is obtained to perform the signal processing.

According to the method of claim 2, a pause band for suspending signal processing in the sensor monitoring terminal device is provided at the end of the transmission signal in the long telegram transmission mode, and the length of the pause band is set to the signal processing cycle.
It is set to 1/2.

[Operation] The present invention is configured as described above, and the signal processing of the sensor monitoring terminal device for signal processing the sensor output and returning the data to the master unit is transmitted each time through the signal line. In the time-division multiplex transmission method that is performed in the signal processing cycle synchronized with the specific pulse, a mode for setting a short message transmission mode for transmitting and receiving a predetermined number of bit data and a long message transmission mode for transmitting and receiving a large number of bit data. Data is transmitted as a transmission signal, and when this mode denter is judged and a transmission signal in the telegram transmission mode is received, signal processing is performed in the above transmission processing cycle, and the transmission signal in the long telegram transmission mode is received. In this case, the signal processing is performed at a cycle substantially the same as the signal processing cycle set by the internal timer, so the transmission in the short message transmission mode and the long message transmission mode is performed. Even when the signal is transmitted, the signal processing of the sensor output can be performed in a substantially constant cycle, and the false alarm does not occur.

Further, at the end of the transmission signal in the long telegram transmission mode, a pause band for suspending signal processing in the sensor monitoring terminal device is provided,
By setting the length of the pause band to 1/2 of the signal processing cycle, the cycle error of the signal processing cycle 1 can be set to ± l / 2.

[Embodiment] FIG. 1 and FIG. 2 are operation explanatory views of an embodiment of the present invention, in which a base unit 1 and a plurality of monitoring and controlling terminals 2a, 2b, 2c are connected to a pair of signal lines 3. Connection from the base unit 1 to each terminal 2a, 2b,
The transmission signal Vs for transmitting and receiving data by accessing 2c is always transmitted, and the signal processing of the sensor monitoring terminal 2 that processes the sensor output and returns the data of the master unit 1 is performed by the specific pulse of each transmission signal Vs. In a time division multiplex transmission system similar to the conventional example, which is performed in a signal processing cycle 1 synchronized with (start pulse ST), a short message transmission mode for transmitting and receiving a predetermined number of bit data and a length for transmitting and receiving a large number of bit data. While transmitting the mode data MD for setting the message transmission mode by the transmission signal Vs, the transmission mode Vs of the short message transmission mode is determined by the mode determination unit provided in the sensor monitoring terminal 2a. Is received, the signal processing is performed in the signal processing cycle 1 described above, and when the transmission signal Vs in the long telegram transmission mode is received, the above-mentioned set by the internal timer is performed. It is obtained to perform the signal processing in issue processing cycle l substantially the same period l '. In the figure,
The shaded squares indicate the signal processing timing. In the embodiment, the format of the transmission signal Vs for transmitting / receiving variable length data is as shown in FIG. 1, and the control data CD or the monitoring data for data transmission in the long telegram transmission mode is used. A byte counter BC for setting the byte length of is provided after the address data AD.

Now, in the embodiment, the transmission signal Vs sent from the master unit 1 to the signal line 3 is a time division multiplex signal as shown in FIG. 7 as in the conventional example, and a predetermined number of bit data is set by the mode data MD. Is set to a short message transmission mode for transmitting and receiving data or a long message transmission mode for transmitting and receiving a large number of bit data, and the byte length of the transmitted and received data in the long message transmission mode is set by the byte counter BC.

Next, when the transmission signal Vs in the short message transmission mode is received, the signal output of the sensor output in the sensor monitoring terminal 2a is, as in the conventional example, as shown in FIG. Is performed in a signal processing cycle 1 synchronized with.
On the other hand, when the transmission signal in the long telegram transmission mode is received, as shown in FIG. 2, the signal processing is performed at the cycle 1'which is substantially the same as the signal processing cycle 1 set by the internal timer. It has become. Therefore, even when the transmission signal Vs in the short message transmission mode and the long message transmission mode is transmitted, the signal processing of the sensor output can be performed at the substantially constant cycles l and l ', and a false alarm may occur. Absent. However, since the length of the transmission signal Vs in the long message transmission mode is generally nl + α, the last signal processing timing nag and the next transmission signal
The initial signal processing timing interval α when Vs is received is not constant.

3 to 5 are operation explanatory views of another embodiment in which the cyclic error of the signal processing cycle is set within a certain range, and the sensor is added at the end of the transmission signal Vs in the long telegram transmission mode. A pause zone X for suspending signal processing in the monitoring terminal 2a is provided, and the length of the pause zone X is 1/2 of the signal processing cycle l.
Setting the error of the signal processing cycle 1 to ±
It can be set to l / 2. FIG. 3 shows the case where there is almost no cyclic error, and FIGS. 4 and 5 show the case where the cyclic error is maximum (± 1/2 l).

EFFECTS OF THE INVENTION The present invention is configured as described above, and the signal processing of the sensor monitoring terminal device that outputs the sensor output as a signal and returns the data to the parent device is constantly transmitted through the signal line. In the time division multiplex transmission method that is performed at a signal processing cycle synchronized with a specific pulse of a transmission signal, a short message transmission mode for transmitting and receiving a predetermined number of bit data and a long message transmission mode for transmitting and receiving a large number of bit data are set. Mode data is transmitted by a transmission signal, and when this mode data is judged and a transmission signal in the short message transmission mode is received, signal processing is performed at the above signal processing cycle, and a transmission signal in the long message transmission mode is performed. When a message is received, the signal processing is performed at a cycle substantially the same as the signal processing cycle set by the internal timer. Even when the transmission signal of the sensor is transmitted, the signal processing of the sensor output can be performed in a substantially constant cycle, and there is an effect that a false alarm does not occur.

Further, at the end of the transmission signal in the long telegram transmission mode, a pause band for suspending signal processing in the sensor monitoring terminal device is provided,
By setting the length of the pause band to 1/2 of the signal processing cycle, there is an effect that the cycle error of the signal processing cycle 1 can be ± 1/2.

[Brief description of drawings]

1 and 2 are operation explanatory views of an embodiment of the present invention, FIGS. 3 to 5 are operation explanatory views of other embodiments, and FIG. 6 is an outline of a time division multiplex transmission system according to the present invention. Block diagram, 7th
FIG. 9 to FIG. 9 are explanatory diagrams of the operation of the above. 1 master unit, 2a, 2b, 2c are terminal unit, 3 signal lines, Vs is the transmitted signal, V _B reply signals, X is resting zone, l, l 'is a signal processing period.

Claims (2)

[Claims] 1. A master unit and a plurality of monitoring and control terminals are connected by a pair of signal lines to constantly transmit a transmission signal for accessing each terminal from the master unit and transmitting and receiving data. In the time division multiplex transmission system in which the signal processing of the sensor monitoring terminal device which processes the sensor output and sends the data back to the master unit is performed in the signal processing cycle synchronized with the specific pulse of each transmission signal In addition to transmitting mode data for setting a short message transmission mode for transmitting and receiving bit data and a long message transmission mode for transmitting and receiving a large number of bit data by the transmission signal, a mode determination unit provided in the sensor monitoring terminal device. If the transmission signal in the short message transmission mode is received, the signal processing is performed at the above signal processing cycle and the transmission signal in the long message transmission mode is received. Division multiplex transmission method when being characterized in that to perform the signal processing by the signal processing period substantially the same period set by the internal timer to. 2. A pause band for halting signal processing in the sensor monitoring terminal is provided at the end of the transmission signal in the long telegram transmission mode, and the length of the pause band is set to 1/2 of the signal processing cycle. The time division multiplex transmission system according to claim 1, characterized in that.