JPH02126167A - Method for detecting disconnection of signal cable - Google Patents

Abstract

PURPOSE:To immediately detect the disconnection of a signal cable by always making the number of high-level signals included in codes even or odd at the time of data transmission. CONSTITUTION:When coded parallel signals are sent from output terminals 1a-1g to input terminals 2a-2g through signal cables 3a-3g, the output level of a parity check terminal 1h is controlled so that the number of the output terminal 1a-1g being at high levels can become an even number. On a receiving side, on the other hand, the number of high-level signals sent to the input terminals 2a-2g and a parity check terminal 2h through the signal cables 3a-3g is counted and checked whether or not the number is always even. When an odd number is found as a result of the checking, it is decided that disconnection or defective contact takes place in a signal line. While the number of high-level signals is always made even in the above-mentioned example, the same effect can be obtained even when the number is always made odd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting disconnection in a signal cable that transmits coded parallel signals.

[Conventional technology]

2. Description of the Related Art In recent years, automation of various operations such as workpiece processing and assembly work at each processing station, and workpiece transport between stations has been rapidly progressing in automobile manufacturing plants. By the way, in the above-mentioned automobile manufacturing factory, many types of vehicles are flowed on the production line in a leveled state, so in order to advance the above-mentioned automation, it is necessary to determine which model of vehicle will be transported next to each processing station. , it becomes necessary to sequentially send vehicle data such as what kind of processing is to be performed on the vehicle type. For this reason, in the automation described above, it becomes necessary to exchange a large amount of data between the various devices installed at each processing station and the operation management device for controlling the operation of each processing station. The number of signal cables bridged in between becomes extremely large. For this reason, the above data is often exchanged using coded parallel signals, so that a large amount of data can be sent using a small number of signal cables.

[Problem to be solved by the invention]

As described above, the number of signal cables can be reduced by transmitting vehicle data and the like using coded parallel signals. However, if vehicle data, etc. is sent as a coded signal, poor contact may occur at the connection between the signal cable and various devices, or if one or more of the signal cables is disconnected, reception may be interrupted. There was a problem in that the data received on the receiving side was completely different from the data sent from the sending side, causing equipment on the receiving side to malfunction.

[Means to solve the problem]

When transmitting data via signal cables between various devices in a factory using coded parallel signals, parity is connected to the input and output terminals of both devices. When transmitting data by providing a check terminal and connecting the above terminals via a signal cable, the number of /% error level signals included in the code should always be an even or odd number. A noise level or low level signal is output from the parity check terminal, and the receiving side counts the number of high level signals, and if the number is not a preset even or odd number, it is determined that the signal cable is disconnected. This is how it was done.

[Effect]

As mentioned above, when transmitting data, the number of high-level signals included in the code is always an even or odd number, and if the number is not a preset even or odd number, it is determined that the signal cable is disconnected. This allows for immediate detection of signal cable breakage.

〔Example〕

FIG. 1 shows an example of transmitting vehicle data and the like as encoded parallel signals using the method according to the present invention. In the figure, (1) is a terminal board installed on a data transmitting device such as an operation management device, and (2) is a terminal board installed on a data receiving device such as a machine tool installed at a processing station. be. (la) to (1g) are output terminals provided on the terminal board (1), (2a) to (2g) are
The input terminals (1h) and (2h) provided on the terminal board (2)
) are parity check terminals provided on terminal boards (1) and (2), respectively, (3a) to (3h) are parity check terminals provided on both terminal boards (
1) This is a signal cable that connects each terminal provided in (2).

Then, input terminals (2a) to (2a) to (3g) are connected from the output terminals (1a) to (1g) to signal cables (38) to (3g).
2g), for example, 3 out of the 7 output terminals (1a) to (1g)
When the two output terminals (1a) to (IC) are at high level, the parity check terminal (1h) is at high level,
Also, when the four output terminals (1a) to (1d) are at high level, the output level of the parity check terminal (1h) is controlled so that the parity check terminal (1h) is at low level, and the terminal board on the output side All terminals (1a) to (1) of (1)
h) The number of high levels is always an even number.

That is, while the number of high-level signals included in the code during data transmission is always an even number, on the receiving side, the input terminal (2a) is connected via the signal cables (3a) to (3h). ) to (2g) and parity check terminal (
2h) Counts the number of high level signals sent and checks whether the number is always an even number. If you do this, the above cables (3a) to (
For example, if one of the signal cables (3a) has a poor contact or is disconnected, and the output terminal (1a) connected to that signal cable (3a) becomes high level, the receiving side Since the number of high-level signals to be counted is an odd number, it is possible to detect a disconnection or poor contact in the signal cables (3a) to (3h). Although the above embodiment describes an example in which the number of high-level signals during data transmission is always an even number, it is of course possible to always make the number of high-level signals an odd number. .

〔Effect of the invention〕

As described above, the present invention reduces the number of high-level signals included in the code when data is transmitted via signal cables between various devices in a factory using coded parallel signals. By switching the output level of the parity check terminal on the transmitting side, the number is always even or odd, and the number is counted on the receiving side to check whether the number is a predetermined even or odd number. If not, it is determined that there is a disconnection, so if a disconnection or poor contact occurs in the signal cable, it can be detected immediately, and at the same time, it is possible to prevent incorrect data from being generated due to a disconnection or poor contact in the signal cable. This can prevent data from being input to the receiving device.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram for explaining a signal cable disconnection detection method according to the present invention. (1a) - (1g) - Output terminal, (2a) (2g) - Input terminal, (1h) (2h) - Parity check terminal, (3a) (3h) - Signal cable. Patent applicant Daihatsu Motor Co., Ltd.

Claims (1)

[Claims] (1) When data is transmitted via signal cables between various devices in a factory using coded parallel signals, both devices transmitting data
When transmitting data by providing parity check terminals outside the input and output terminals and connecting the above terminals via signal cables, the number of high-level signals included in the code is always an even or odd number. Output a high level or low level signal from the parity check terminal on the transmitting side so that A method for detecting a signal cable breakage, characterized in that it is determined that a signal cable breakage occurs when a signal cable breakage occurs.