JPS587950A - Automatic testing device for loop-like transmission line - Google Patents

Abstract

PURPOSE:To always keep a transmission line to a normal state by automatically sending testing data to test a loop transmission line when no transmission data are sent to the loop transmission line. CONSTITUTION:A frame sending circuit 5 in a main controlling device sends a frame including a frame synchronizing pattern to a transmission loop TX. A transmission request detecting circuit 8 is connected to the receiving terminal of the TX and detects whether a transmission request REQ fromany transmitting/ receiving device is put on a prescribed position of the frame sent from the circuit 5 or not. When detecting the REQ, the circuit 8 makes a transmission accknowleging signal preparating circuit 7 output a transmission acknowleging signal. At the absence of the REQ, the circuit 8 sends a test data transmitting signal A to the circuit 5. At the sending of the succeeding frame, the circuit 5 puts an output data from a test data sending circuit 6 on the prescribed position of the frame. The receiving terminal of the TX is connected to a receiving loop RX and the data transmitted to the RX reaches a matcher 9. The circuit 9 compares the received test data with the output of the circuit 6 to detect errors.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a loop-shaped transmission path automatic test device, and in particular,
The present invention relates to a test device that automatically sends test data to test a loop transmission path by utilizing the times when no transmission data is sent to the loop transmission path.

Conventionally, a loop-shaped transmission line is configured as shown in Fig. m'1. However, the transmission 1η loop transmission line TX and the reception 1
On the t1 loop transmission line Rx, the main control device 1 and a plurality of transmitting/receiving devices 2 to 4 are arranged (~, and the main control device 1 sends out a frame with a predetermined number of bits in which the frame same Jυj pattern is inserted at the beginning). The signals to be carried at each bit position on the frame are determined by the frame structure shown in Fig. 2. That is, the frame synchronization pattern B F
l) , Transmission permission signal ACK, Transmission request REQ, Destination admit DA, Outgoing address OA, Transmission data DATA
etc., are each assigned a predetermined bit length to a predetermined position 1a on the frame. For example, when data is to be transmitted from the transmitting/receiving device 4 to the transmitting/receiving device 8 shown in FIG. . When the host device 1 detects the send request REQ (8) in the frame received at the transmitting loop TxO receiving end, it determines whether transmission is possible or not, and if it is possible to send, it moves to the next room. A transmission permission signal ACK is placed on a predetermined position of the signal and sent to the transmission loop Tx. I am monitoring the transmission loop Tx in the transmission/reception bag ft1t 4, and the transmission permission IJJf number A is
When CK is detected, the destination address DA, the originating address OA, and the transmission data DATA are placed on the frame.

In Royal Mail Bag +11, the receiving end of the transmitting loop TX is connected to the transmitting end of the receiving loop Rx, so the frame is sent as is to the receiving loop Rx. The transmitting/receiving device 8 is
When it monitors the reception loop Rx and detects that the destination address DA in the frame points to its own station, it takes in the origination address OA and the transmission data DATA. Data is exchanged between arbitrary transmitting/receiving devices using the procedure described above. Note that when the transmission request REQ is output from multiple transmitting/receiving devices, the master device IVi selects one of them with priority and issues a transmission permission ACK specifying the selected station.
Send out. In such a loop-shaped transmission line, the amount of data between each transmitter/receiver is generally not that small, so there is not always a request for transmission. In other words, when there are few transmission requests, there are many frames in which no transmission data is carried, and the transmission path is wasted.

An object of the present invention is to test a transmission line by sending test data by effectively utilizing such empty frames, and to always maintain the transmission line in a normal state.

The test device t of the present invention includes a main control device and a plurality of transmitter/receiver devices arranged on a loop-shaped transmission path, and sends frames in a predetermined format including a frame synchronization pattern from the main control device to the transmission loop, and A transmission request from a transmitting/receiving device is sent to a predetermined position of the frame, and when the main control device detects a transmitting request from any of the transmitting/receiving devices at the receiving end of the transmitting loop, the transmission request is sent to a predetermined position of the next frame. When the transmitting/receiving device that sent the transmission permission signal and issued the transmission request detects the transmission permission signal from the frame, it places the destination address and transmission data in a predetermined position of the frame, and the main control device cancels the transmission loop. The frame received at the receiving end of the transmitter/receiver is sent to the receiving loop, and each transmitting/receiving device monitors the receiving loop and is configured to receive the transmitted data sent in that frame when the destination address points to its own station. In the loop-shaped transmission line, the main control device is connected to the transmission loop receiving end and outputs a transmission permission signal when detecting the transmission request, and outputs a test data transmission signal when the transmission request is not detected. a test data sending circuit that sends test data; and a frame that selectively selects the transmission permission signal or the test data according to the output of the transmission request detection circuit and sends the selected signal to a corresponding position on the frame. a sending circuit; and a verification circuit that matches the test data received at the receiving end of the receiving loop with the output signal of the test data sending circuit, and when the receiving end of the sending loop does not detect the transmission request, the following: The transmission loop is tested by transmitting the test data to frame A of the transmitter and comparing the test data received at the receiving end of the receiving loop with the output signal of the test data transmitting circuit.

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 8 is a block diagram showing one embodiment of the present invention, showing the configuration of the main control device. That is, the frame sending circuit 6
sends a frame containing the frame synchronization pattern RFP to the transmission loop TX. The transmission request detection circuit 8 is connected to the receiving end of the transmission loop Tx, and determines whether the transmission request IζIDQ from any of the transmitting/receiving devices 2 to 4 is placed at a predetermined position of the frame transmitted from the frame transmitting circuit 5. If the transmission water absorption REQ is detected, the transmission 7-
Transmitted from I signal generation circuit 7, i'l town'i'HriA
CK is output, and transmission request RP; If Q is not detected, test data is sent (*-QA is output and sent to the frame output circuit 5.

When the frame is sent out, the next frame is sent out, the above-mentioned sender accepts Q]' and ACK is sent out (1).

That is, when there is a transmission request, the transmission permission signal ACK is sent.
and sends test data if there is no transmission request. The freno board carrying the test data receives transmission permission signals A and CK.
Since no data is carried on the transmission line (7), no transmission data is carried on the transmission line (7) from any of the transmitting/receiving devices. Then, since the frame is connected to the receiving loop Rx at the transmitting Rouso TXQ receiving end, the frame is sent to the receiving loop flx and reaches the receiving loop RxO receiving end. The main control device W uses a matching circuit 9 to match the test data in the frame with the output data from the preview data sending circuit 6, and outputs a 4-bit match signal B if they do not match. This makes it possible to detect transmission errors on the transmission path. Transmitting/receiving devices 2 to 4, the transmission request REQ may be placed on the frame in which the test data is placed on the transmission loop Tx described in -. In this case, the transmission request detection circuit 8 of the inter-monarchy device detects the transmission request REQ in the frame ``], and transmits the next frame with the transmission permission signal ACK on the frame transmission path A. It is possible to send and receive data as before,
And, the above-mentioned frame is sent to the receiving loop Rx. This is because the above-mentioned verification operation can be performed at the receiving end of the receiving loop Rx after being sent out. In other words, the provision of the test circuit (8) according to this embodiment does not affect the normal data exchange operations between the transmitting and receiving devices. 21i: When transmitting the above test data, a special address is transmitted as the destination address of the frame, and each transmitting and receiving device
There is no problem in confirming whether the receiving operation is correct or not by extracting test data when the special address is detected and comparing it with a certain pattern.

FIG. 4 is a diagram showing an example of a signal state placed on a frame. In this case, the transmitting/receiving device [2 The frame arrives at the receiving end of the transmitting loop TxO with transmission data (see Fig. 4, 10).The frame is directly sent to the receiving loop Rx and is received by the destination transmitting/receiving device. The transmitting/receiving devices 2 to 4 also do not carry the transmission request REQ.Therefore, the frame 11 sent next from the main control device 1 contains the transmission permission number 4h'A.
No CK is sent (total is 10) and test data 12 is sent. Then, for example, a transmission request REQ from the transmitting/receiving device 3 is placed at a predetermined position and arrives at the receiving end of the transmission loop (see FIG. 4, 11). The 71 norm is then sent to the receiving loop Rx, and errors in the test data 12 are detected by the verification circuit 9 at the receiving end of the receiving loop RxO. On the other hand, the frame sending circuit 5 sends a signal ACK (content &
-1, 3'' or 11'') is sent completely, a transmission request 1 and EQ is placed from the transmitting/receiving device 2 at a predetermined position of the frame,
The transmitter/receiver jf8 transmits the transmitted data (the transmitted data is omitted in FIG. 4). As described above, when there is no transmitter request, the test data is sent in the next frame and a verification test operation is performed at the receiving end, and in the next frame when there is a transmitter request, data is exchanged using the same operation as before. can be done.

As described above, in the present invention, when no transmission request is output to the loop-shaped transmission line, the loop-shaped body 1 base is transmitted by transmitting the test 7'-to-R frame. 7, testing of Mitsuo Kurori, etc.: Therefore, the loop transmission line can be effectively used and tested during off-peak hours, which is extremely convenient for maintenance purposes. Since the tests described above are automatically carried out, it is possible to eliminate special test drive work on the part of the author.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the configuration of a loop-shaped transmission h'h to which the present invention is applied. FIG. 3 is a diagram showing an embodiment of the present invention, and FIG. 4 is a diagram showing an example of frame No. 14 of frame H in the above embodiment. . Figure 1/e-ite, 1”・,-7E itf'l al
l Sample 111.2-4-a-reception (=device, 5... frame sending circuit, 6... test data sending circuit, 7...
Sending one word permission cultivation) creation circuit, 8... Transmission request detection circuit, 9... Verification circuit, A... Test data sending foil No.
B...Unmatched number 1, Tx...Transmission loop, Rx...
...Reception loop, BTi'P...Frame synchronization pattern, ACK...Transmission permission number 1d, REQ...Transmission request, 1]A...Destination address, OA...Originating address, I) ATA...Transmission data. Daikonjin ``jP: 1 Rinshisho H'' Danso

Claims (1)

[Claims] A main control device and a plurality of transmitting/receiving devices are arranged on a loop-shaped transmission path, and frames in a predetermined format that match the frame synchronization pattern are sent from the royal system to the transmission loop,
A transmission request from each transmitting/receiving device is sent to a predetermined position of the frame, and when the main control device detects a transmission request from any of the transmitting/receiving devices at the receiving end of the transmitting loop, it transmits the request to a predetermined position of the next frame. When the transmitting/receiving device that sent out the permission signal and issued the transmission request detects the transmission permission signal from the frame, it places the destination address and transmission data in a predetermined position of the frame, and the main control device sends the transmission request to the receiving end of the transmission loop. Sends the received frame to the reception loop,
In a loop-shaped transmission path configured such that each transmitting/receiving device W monitors a receiving loop and receives transmission data sent in a frame of seven when the destination address points to its own station, the main control device a transmission request detection circuit that is connected to the transmission loop receiving end and outputs a transmission permission signal when detecting the transmission request and outputs a test data transmission signal when no transmission request is detected; and a test data transmission circuit that transmits the test data. a frame sending circuit that selectively selects the transmission permission signal or the test data according to the output of the transmission request detection circuit and sends it to the corresponding position on the C frame; a verification circuit that compares the test data sent by the test data with the output signal of the test data sending circuit, and when the receiving end of the sending loop does not detect the sending request, the test data is sent in the next frame, and the receiving end of the receiving loop An automatic test device for a loop-shaped transmission line whose function is to test the transmission loop by comparing the test data received at the receiving end with the output signal of the test data sending circuit.