Model 979 Series Helium Mass Spectrometer Leak Detector
DRAFT 9/15/03
A-3
A.2 Optically Isolated Inputs
Table A-2 provides the input information for the I/O discrete connections.
Figure A-3 shows the input circuit sketch. Level inputs are optically isolated 5 VDC to
24 VDC, 3600 Ohm resistive loads, and require a 200 ms minimum pulse width.
Figure A-3
Optically Isolated Input Circuit Sketch
Table A-2
Summary Table of Optically Isolated Inputs
Pin
Input Name
Momentary
or Level
Description
1
Input Common
N/A
Customer-supplied GND for all P101 inputs.
21
START IN
Momentary
>200 ms High Pulse to initiate 979 Roughing Mode.
22
VENT IN
Momentary
>200 ms High Pulse to initiate 979 Vent Mode.
23
HOLD IN
Momentary
>200 ms High Pulse to initiate 979 Hold Mode.
20
SPARE_IN_5
Spare input 5.
24
AUTOCAL
Momentary
>200 ms High Pulse to initiate an AUTOCAL cycle.
25
ZERO
Momentary
>200 ms High Pulse to initiate a ZERO function.
26
SPARE_IN_3
Spare input 3.
27
SPARE_IN_4
Spare input 4.
Customer
979 Series
5-24 VDC
I/O-21
I/O-27
I/O-1
+
Summary of Contents for 979 Series
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