JPH02186748A - Communication loop back test circuit - Google Patents

Abstract

PURPOSE:To prevent malfunction at the time of a test and to easily conduct a loop back test by putting a delay line between the connection of a transmission line and a reception line at the time of the communication loop back test by means of a loop back test device. CONSTITUTION:When a channel controller 10 transmits transmission data 70 to a device controller 20 through a transmission line 50 in a normal action, the controller 20 returns a response with respect to data 70 to the controller 10 through a reception line 60. At that time, the delay line 40 is detached. When a test signal 90 is inputted at the time of the communication loop back test, a selector operates and the line 50 and the line 60 on a common interface are shortly connected, whereby the delay line 40 is interposed between both lines 50 and 60. When the test is conducted in such a way, loop back data is given delay and it returns to a channel control circuit 100. Consequently, malfunction hardly occurs.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to channel control'? The present invention relates to a communication return test circuit between a device and a device control device, and particularly to a communication return test circuit having a function of giving a delay to returned data.

[Prior Art] Generally, a channel control G9 device and a device control device are installed at a distance, and the distance of a common interface that connects the two and allows them to communicate becomes long. For this reason, the channel system U4 device a and the device control device are each designed in consideration of delay time, that is, designed on the premise that there is a certain delay time between data transmission and reception.

During a communication return test, the transmitting and receiving lines of the channel control device are connected in a short circuit to send outgoing data to the receiving line, but a short cable, e.g.
If only a cable with a maximum length of 100 mm is used, the required delay time cannot be met, resulting in malfunction.

For this reason, conventionally, during communication loopback tests, in order to prevent the above-mentioned malfunctions, a long loopback cable that satisfies the above-mentioned fixed time delay was used to connect the transmitting and receiving lines.

[Problems to be Solved] As mentioned above, in the conventional communication loopback test, there was a problem in that a long cable corresponding to the data delay between the channel control device and the device control device had to be prepared.

The present invention has been made in view of the above-mentioned problems, and aims to provide a communication return circuit that does not require a long cable during a communication return test and can be bypassed during normal communication.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a data transmitting/receiving line of a channel control device that is interposed between the data transmission and reception lines so as to be freely accessible and separable, and that data is sent from the channel control circuit to the device control device during one communication return test. A communication loopback test circuit that delays transmission data and connects it to the reception line of the channel control circuit, wherein the channel control circuit and the device control device are connected through a common interface during normal operation, and during loopback testing. In the channel control device, data to be transmitted to the device control device is connected to a reception line of the own channel control device via a delay line to receive Q data.

[Embodiment 1] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

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

In the figure, 10 is a channel control device, 20 is a device control device, and the two are connected by a transmission line 50, a reception line 60, etc., which serve as a common interface. Further, 100 in the figure is a channel control circuit.

The loopback test device 30 is located within the channel control device 10 and is connected to the transmission line 50 and the reception line 6 using the test signal 90.
0 can be connected in a short-circuit manner inside the device, and also has a delay line 40 interposed between the transmission line 50 and the reception line 60 which are switched and connected by the selector. The delay time caused by the delay line 40 is set to a time such that a predefined delay occurs between the channel control device IO and the device control device 20.

Next, the operation of this embodiment will be explained.

In normal operation, the channel control device 10 transmits data 70
When the data is sent to the device control device 20 via the transmission line 50, the device control device 20 sends a response to the transmission data 70 to the channel control device 10 via the reception line 60.
At this time, the delay line 40 is disconnected.

When the test signal 90 is input during the communication return test, the selector is activated and the transmission line 5 on the common interface is
0 and the receiving line 60 are connected in a short circuit, and both lines 5
A delay line 40 is interposed between 0.60 and 0.60. If the test is performed in this manner, the return data is returned to the channel control circuit 100 with a delay, so that no malfunction occurs.

[Effects of the Invention] As described above, the present invention can prevent malfunctions during a communication return test using a return test device by inserting a delay line between the connection of the transmission line and the reception line. Further, there is an effect that there is no need to prepare a long cable, and it becomes possible to perform a folding test easily.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention. lO: Channel control device 20: Device control device 30: Folding test device 40: Delay line 50: Transmission line 60: Reception line 70: Transmission data 80: Received data 90: Exam Shinkin Bank 100: Channel control circuit

Claims (1)

[Claims] Intervening between the data transmission and reception lines of the channel control device so as to be freely accessible and detachable, and connecting to the reception line of the channel control circuit by giving a delay to the transmission data sent from the channel control circuit to the device control device during a communication return test. The communication loopback test circuit connects the channel control circuit and the device control device through a common interface during normal operation, and transmits data to be transmitted to the device control device within the channel control device through a delay line during the loopback test. A communication loopback test circuit characterized in that the circuit is connected to a reception line of a self-channel control device via a communication line to receive data.