Figure 10-5 Comparison result signal output circuit
10.1.2.2 DC Isolation Input Signal
DC isolation input signals include the /EXT_TRIG and /KEY_LOCK signals.
The /EXT_TRIG signal (pin 12 and pin 13) is input to the LED cathode side of the optocoupler.
The instrument is triggered when the signal increases from LOW to HIGH. The optocoupler LED
(anode side) can be driven by an internal pull-up voltage (+5 V) or an external voltage
(EXT.DCV2).
The /KEY_LOCK signal (pin 25) is input to the optocoupler LED (on the cathode side). As long as
this is low level, the keys on the front panel of the instrument will all be locked. The optocoupler
LED (anode side) can be driven by internal voltage (+5V) or external voltage (EXT.DCV2).
The input circuit configuration of the DC isolation input signal is shown in Figure 10-6.
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