| 摘要 |
PURPOSE:To detect the trouble of a relay within a short time, by inserting a plurality of load resistors between one terminals of plural relay contacts and a power source voltage applying point and connecting the other terminals of the above mentioned relay contacts to the voltage output terminal of a pro gram power source by a switch circuit. CONSTITUTION:One terminal of each resistor 32 in a diagnostic resistor unit 31 is connected to a power source voltage applying point of 5V for example. The other terminals of the resistors 32 are connected to one terminals of six relay contacts S1, S6 in a relay matrix circuit 15. The movable contact of each diagnostic relay 34 in the diagnostic relay circuit 33 is connected to the other terminal of the diagnostic contact relays 34 has two fixed contacts and one of the fixed contacts is connected to an earth potential point while the other fixed contact is connected to each program power source. By this mechanism, a digital signal can be sent corresponding to the operational state each relay contacts and the trouble of a relay can be detected within a short time.
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