JPS63288535A - Communication control unit - Google Patents

Abstract

PURPOSE:To attain the version setting of a unit main body without an error without needing a knowledge to a transceiver by deciding automatically the version of the transceiver and switching the version of a transmission signal driver. CONSTITUTION:The level of the reception signal from a transceiver 20 is detected by a reception signal detecting circuit 24 of a communication control unit main body 20 and a non-communicating condition, in which the signal level comes to be constant, is detected. A level constant detecting circuit 25 automatically decides from the reception signal direct current level of the non- communicating condition whether a transceiver 22 is a version 1 or a version 2, and through a switching circuit 26, a transmission signal driver 27 for the version 1 or a transmission signal driver 28 for the version 2 is automatically selected. As the result, without needing the knowledge to a transceiver, the version setting of the unit main body is executed without an error by the automatic decision and automatic selection.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a carrier detection multiple access system with a collision detection function (hereinafter referred to as C8MA/CD system) when a terminal device is connected to a C8MA/CD bus. The present invention relates to a communication control device that detects differences in versions of transceivers and adjusts transmission signals to the same version.

2. Description of the Related Art A conventional communication control device of this type has a configuration as shown in FIG.

That is, in FIG. 2, 10 is a CS MA/CD cable (bus), and 11 is a transceiver that outputs the signal on the C8 MA/CD bus and transmits and receives it to the terminal device side. It is roughly divided into two types depending on the difference. This is assumed to be version 1 and version 2, and the differences in the signaling systems between the two are shown in FIG.

12 is a transceiver cable, 13 is a version setting switch for setting the version of the transmission signal driver described later to version 1 or 2, and 14 is a transceiver 11.
15 is a version 2 transmission signal driver.

Next, to describe the operation, the operator determines version 1 or 2 of the transceiver 11 and operates the version setting switch 13 based on that determination.
The transmission signal driver 14 or 15 of a version that matches the transceiver 11 is selected and switched.

Problem to be Solved by the Invention In other words, in the conventional communication control device described above, the operator can determine the version of the transceiver and set a switch to match the version of the communication control device itself with the version of the transceiver. conformity). Therefore, there is a problem in that the operator is required to have knowledge about the transducer and there is a possibility that the version setting switch may be set incorrectly.

The present invention has been made to solve such conventional problems, and provides an excellent communication control device that does not require operator knowledge of transceivers and can set the version of the device itself without error. The purpose is to

Means for Solving the Problems In order to achieve the above object, the present invention provides a detection circuit that detects a received signal from a transceiver, a detection circuit that detects that the level of the received signal has become constant, and a transmitter. It is equipped with a switching circuit that performs version switching for the signal driver.

Effects The present invention has the following effects due to the above configuration.

First, the level of the received signal from the transceiver is detected by a detection circuit, and when the signal level becomes constant, that is, the state of no reception communication (see FIG. 3) is detected by the detection circuit.

Therefore, the received signal DC level during the non-communication state is
For example, if it is 0.16V or higher, the transceiver automatically determines that it is version l, and if it is OV, it automatically determines that it is version 2.

Based on the determination, the switching circuit sends an appropriate signal to the transmission signal driver (transmission signal driver for version 1 and transmission signal driver for version 2), selects the transmission signal driver that matches the version of the transceiver, and automatically switches. I do.

Embodiment FIG. 1 is a block diagram showing a schematic configuration of a communication control device according to an embodiment of the present invention. In FIG. Communication control device body, 21 is CS MA/CD cable, 22
is a transceiver (version I or 2).

The communication control device main body 20 includes a receiver 23 that receives a received signal from a transceiver 22, a detection circuit 24 that detects the level of the received signal, and a detection circuit 24 that detects when the received signal level has become constant, that is, when no communication is received. It has a detection circuit 25 that detects the state, and a driver version switching circuit 26 that automatically switches between the version 1 transmission signal driver 27 and the version 2 transmission signal driver 28 based on the outputs from both the circuits 24 and 25. It consists of

In operation, the detection circuit 24 monitors the received signal from the transceiver 22.

When the reception signal from the transceiver 22 remains at a certain level (no communication state) for a certain period of time, the gap detection circuit 25 notifies the switching circuit 26 of this as a pulse.

The switching circuit 26 is triggered by a pulse from the detection circuit 25 and selects a transmission signal driver 27 or 28 for version 1 or 2 that matches version 1 or 2 of the transceiver 22 in accordance with the received signal level from the detection circuit 24. to perform automatic switching.

Effects of the Invention As is clear from the above embodiments, the present invention has the following advantages:
The transceiver version is determined by , and the transmission signal driver version (transmission method) is automatically switched based on the determination information.
without requiring operator knowledge of transceivers.

and without errors and compatible with the transceiver version.
The version of the communication control device itself can be set.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a communication control device that is an embodiment of the present invention, FIG. 2 is a block diagram showing a schematic configuration of a conventional communication control device, and FIG. 3 shows a version I transceiver and a version FIG. 2 is a waveform diagram showing the difference in signal system between the second transceiver and the second transceiver. 20・Communication control device main body, 21 , , CSMA /
CD cable, 22...transceiver, 239. Received signal receiver, 24...Received signal detection circuit, 25. Constant level detection circuit, 26. ...Driver version switching circuit, 271. Transmission signal driver for version 1, 28...
Transmission signal driver for version 2. Name of agent: Patent attorney Toshio Nakao and 1 other person 20
---11FJ'Lq Table IL: ¥-A Book 2nd Figure

Claims (1)

[Claims] Means for automatically determining the version of a transceiver provided in a carrier detection multiple access system bus with a collision detection function based on the DC level of a received signal during a receiving non-communication state, and the version of the transmitting signal driver based on the determination information. and means for automatically switching to match the version of the transceiver.