JPH0824390B2 - Multiplexer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex transmission device using a time division system, and is used, for example, in a system for controlling a lighting load, an air conditioning load, an electric lock, etc. by the multiplex transmission. is there.

[0002]

2. Description of the Related Art FIG. 3 is a schematic configuration diagram of a conventional general time division multiplex transmission device. In this device, one parent device A and a plurality of terminal devices B1, B2, ... Are connected via a two-wire transmission line L such as a coaxial cable or a twisted pair wire. 6A and 6B, the time-division multiplex transmission signal sent from the base unit A to the transmission line L and the terminal units B1, B2, ... Reply to the base unit A via the transmission line L. The waveforms of the reply signals are shown. The time division multiplex transmission signal is 1
In the frame FR, a start pulse ST indicating the start of signal transmission, an address pulse AD for designating a terminal device Bi (i = 1, 2, ...) To communicate with, and an operation for controlling the operation of the terminal device Bi. It includes at least a control pulse DT and a reply waiting time zone RT for receiving a reply signal (monitoring pulse) from the terminal device Bi. The address pulse AD and the control pulse DT are composed of, for example, a serial signal of a plurality of bits meaning that the long voltage pulse is 1 and the short voltage pulse is 0. In the reply waiting time zone RT, for example, by applying a voltage between the transmission lines L on the side of the base unit A and shorting the lines of the transmission lines L on the side of the terminal device Bi via a resistor, for example, ,
A multi-bit serial signal, which means that the long current pulse is 1 and the short current pulse is 0, is returned to the master unit A. The address pulse AD and the control pulse DT are sent from the base unit A as low impedance voltage signals, and in each terminal device Bi, a rectifier and a smoothing capacitor are connected between the transmission lines L to obtain an operating power supply. The address pulse AD included in the time division multiplex transmission signal transmitted from the base unit A is changed so as to cyclically poll each terminal device Bi, and only one terminal device Bi having the same address is used. The control operation and the reply operation according to the control pulse are performed. When the start pulse ST is received from the transmission line L, the terminal device Bi receives the subsequent address pulse AD and collates with its own address. If the addresses do not match, it waits for the next start pulse ST to be received. If the addresses match, the control pulse DT following the address pulse AD
Is received, and the control operation is performed according to the control pulse DT. Further, a reply signal as shown in FIG. 6B is sent in the reply waiting time zone RT following the control pulse DT.

FIG. 4 shows the internal structure of the terminal B1. The transmission processing unit 1 has a function of receiving a multiplex transmission signal transmitted from the master unit A and returning a reply signal, and is usually configured by using a microcomputer. The setting device C is connected to the terminal device B1.
The setting device C is used to set the function of the terminal device B1. The function of the terminal device B1 includes, for example, the type of the terminal device for monitoring the operation of a wall switch or the like, the terminal device for load control, and the like, as well as the address of the terminal device B1. As described above, the power source of the terminal device B1 is supplied from the multiplex transmission line L. Therefore, when the multiplex transmission signal from the master device A is stopped due to a power failure or the like, the power source of the terminal device B1 is cut off. Even in such a case, the non-volatile memory 2 is built in the terminal device B1 so that the information of the terminal device B1 is not lost. The non-volatile memory 2 is, for example, an EEPROM.
The advantage is that the stored contents are not erased even when the power is cut off, but on the other hand, there is a drawback that the access speed is slow. Therefore, when the power of the terminal device B1 is turned on, information is read from the non-volatile memory 2 to the volatile memory 3, and the volatile memory 3 is read from the transmission processing unit 1.
Has been proposed. Volatile memory 3
Is composed of, for example, a RAM and has a drawback that the stored contents are erased when the power is cut off, but instead has an advantage that the access speed is fast. In this way, by using the two types of memories 2 and 3 together, it is possible to achieve both retention of stored contents when power is cut off and high-speed access speed.

[0004]

In the above-mentioned conventional technique, the multiplex transmission process and the communication process with the setting device C cannot be simultaneously executed in parallel because of the processing speed of the transmission processing unit 1. That is, as shown in FIG. 5A, when the communication process with the setting device C starts, the multiplex transmission reception enable signal of the terminal device B1 becomes Low as shown in FIG. 5C.
It becomes a level, and multiplex transmission processing cannot be performed. afterwards,
Even if the communication process with the setter C is completed, the multiplex transmission reception enable signal is held at the Low level until the process for creating the function table is completed, as shown in FIG. Multiplex processing cannot be performed. For this reason,
In the meantime, even if the terminal device B1 needs to be controlled or monitored by multiplex transmission, there is no response until the communication process with the setting device C and the function table creation process are completed, and the user is requested to wait. There was a problem that this would happen.

Therefore, in order to prevent the multiplex transmission processing from being stopped, it is conceivable that the multiplex transmission processing and the communication processing with the setting device C are performed by different microcomputers, but the multiplex transmission is performed during the creation of the function table. When the terminal device B1 is accessed in the processing, there is a possibility that a malfunction may occur. That is, if the function table is rewritten in the middle of receiving data, for example, the addresses do not match originally, but the addresses match, and multiple terminal devices simultaneously When the access data is accessed, the reply data overlap each other, and there arises a problem that the master device A cannot receive the reply data normally.

The present invention has been made in view of the above points, and an object of the present invention is to provide a multiplex transmission device in which a function table for determining the operation of a terminal is stored in a memory of the terminal. The purpose is to prevent the stop or malfunction of the multiplex transmission process due to the rewriting of the function table.

[0007]

In order to solve the above problems, the present invention provides a common transmission line for a plurality of terminals B1, B2, ... To which unique addresses are assigned, as shown in FIG. It is connected to the base unit A via L, the control pulse is transmitted to each of the terminals B1, B2, ... In response to the address designation from the base unit A, and the monitoring pulse is returned from the addressed terminal unit to the base unit A. In the multiplex transmission device configured as described above, each terminal device B1, B2, ..., As shown in FIG. 1, a first transmission processing unit 1 that executes a multiplex transmission process with the master unit A,
A setting device C for setting the function of the terminal device, a function table for storing the function of the terminal device, and a second transmission process for transmitting and receiving information between the setting device C and the function table. And the function table rewriting timing is set to a reply pulse waiting time zone of a monitoring pulse in a multiplex transmission signal that does not match its own address.

[0008]

In the present invention, when the address of the multiplex transmission signal transmitted from the base unit A to the terminals B1, B2, ... The function table is rewritten during the monitoring pulse return waiting time in the multiplex transmission signal, and the multiplex transmission signal is not sent from the master unit A in that time zone, and the terminal device Since it does not perform the reply operation, there is no problem even if the receiving operation and the reply operation of the multiplex transmission process are suspended, and apparently the multiplex transmission process and the rewriting process of the function table can be simultaneously performed in parallel. become.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a terminal device B1 used in the multiplex transmission apparatus of the present invention.
This configuration is shown as an example. First transmission processing unit 1
Has a function of receiving a multiplex transmission signal transmitted from the parent device A to receive control information and returning a monitoring pulse. The second transmission processing unit 4 has a function of performing communication processing with the setting device C. First and second transmission processing units 1,
4 is preferably configured by using two microcomputers so that the multiplex transmission processing and the communication processing with the setting device C can be processed at the same time. However, a microcomputer with a high processing speed is used and time-division processing is performed. It is also possible to execute two processes at the same time. It is also possible to configure with hard logic.

Next, the nonvolatile memory 2 is, for example, an EEP.
It consists of a ROM, and the stored contents are not erased even when the power is cut off. The nonvolatile memory 2 is accessed by the second transmission processing unit 4 and stores the function table of the terminal device B1. The volatile memory 3 is, for example, a RAM, and the stored contents are lost when the power is cut off.
The access speed is faster than that of the nonvolatile memory 2. The function table of the nonvolatile memory 2 is transferred to the volatile memory 3, and the function table is accessed by the first transmission processing unit 1 to determine the operation of the terminal device B1.

Next, the control circuit section 5 constantly monitors the state of multiplex transmission, and when writing is made from the setter C to the nonvolatile memory 2 via the transmission processing section 4, it coincides with its own address. The control signal for starting the reading of the non-volatile memory 2 is output during the reply waiting time period in the multiplex transmission signal which has not been received. By this control signal, the data in the non-volatile memory 2 is read and a function table is created on the volatile memory 3. The nonvolatile memory 2 is, for example, EEPRO.
Since it takes time to read the data, the control circuit unit 5 starts reading the nonvolatile memory 2 so that the reading of the nonvolatile memory 2 is completed by the end of the reply waiting time period. The control signal of 1 must be limited to the beginning part of the reply waiting time zone. This operation is shown in FIG. In FIG. 2, (a) shows a period of communication processing with the setting device C by the second transmission processing unit 4. This period is much longer than one frame of the multiplex transmission signal. Next, (b) shows the period T of the process of creating the function table.
3 and (c) show a control signal generation period T2.
(D) is a multiplex transmission signal, and its reply waiting time zone RT
The function table is rewritten.

According to this structure, multiplex transmission is possible even when the function table is being changed by the setter C, the control data is transmitted from the master unit A to the terminal unit B1, and the terminal unit B1 is transmitted. It is possible to transmit the operation data of the switch in the terminal device B1 and the monitoring data indicating the state of the terminal device B1 from B1 to the master device A. Further, in the conventional example, simultaneous access of the function table is performed not only when the function table is changed by the setter C but also when the function table is read in order to confirm how the function table is set. In order to avoid the above, the multiplex transmission process in the terminal device B1 is stopped. However, since reading the function table does not directly affect the multiplex transmission, it is not necessary to stop the multiplex transmission process.
In the present invention, since the possibility of simultaneous access to the function table is eliminated, it is not necessary to stop the multiplex transmission process, and the user operates the switch of the terminal device B1 even while operating the setting device C, The control state of the terminal device B1 or its change can be monitored from the master device A, and the terminal device B1 can be made to respond without waiting for the completion of the operation of the setting device C.

In the description of the embodiment, as shown in FIG. 3, the transmission line L is connected to two terminal devices B1 and B2, but the number of terminal devices is not limited to this. However, if an 8-bit address is assigned, a maximum of 256 units can be connected.

[0014]

In the multiplex transmission apparatus of the present invention, the rewriting of the function table that determines the operation of the terminal can be performed completely in parallel with the multiplex transmission processing, and therefore, it is necessary to stop the multiplex transmission. Therefore, there is an effect that it is possible to eliminate the time during which the terminal does not operate.

[Brief description of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a waveform chart showing the operation of the present invention.

FIG. 3 is a block diagram showing a schematic configuration of a conventional multiplex transmission device.

FIG. 4 is a block diagram showing an internal configuration of a terminal used in a conventional example.

FIG. 5 is a waveform diagram showing an operation of a conventional example.

FIG. 6 is a waveform diagram showing a multiplex transmission signal and a reply signal.

[Explanation of symbols]

 A base unit B1 terminal device B2 terminal device C setting device L transmission line 1 transmission processing unit 2 non-volatile memory 3 volatile memory 4 transmission processing unit 5 control circuit unit

Claims (1)

[Claims] 1. A plurality of terminals to which unique addresses are assigned are connected to a master unit via a common transmission line, and a control pulse is transmitted to each terminal unit by address designation from the master unit and is addressed. In the multiplex transmission device in which the monitoring pulse is returned from the terminal device to the master device, each terminal device has a first transmission processing unit that executes a multiplex transmission process with the master device and a function of the terminal device. A setting device for setting, a function table for storing the function of the terminal device, and a second transmission processing unit for transmitting and receiving information between the setting device and the function table. A multiplex transmission device characterized in that the rewriting timing of the table is set in a reply waiting time zone of a monitoring pulse in a multiplex transmission signal which does not match its own address.