Hioki DSM-8542, Instruction Manual, Page: 128 / 140

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(3) Handler input signal
The input signals are output by the cathode of an LED in the photocoupler through
a current limiting resistance.
The anode side of the LED is connected to the 5V power source inside. Output
the handler output by an open collector or TTL output.
The common terminal of the input signals is DC-isolated from the internal circuit.
An equivalent circuit of the input circuit is illustrated in Fig. 9.2.
Input Characteristics
Maximum Input Voltage
LOW HIGH
Maximum Input
Current
0.5 V 5 V 1.2 mA
[Notice]
Output the output of the handler side by an open collector or by TTL output.
Do not impress voltage of more than 5V to input signals.
Fig. 9.2 Handler Input Circuit
[Notice]
The input-signal common terminals (Pins 2 and 20) of the handler interface, as
well as common terminals (connector outer conductors) of the external trigger
input (“EXT TRIGGER”) and interlock input (“INTERLOCK”) on the rear panel, are
connected.