Allen-Bradley 1756-CFM, Руководство пользователя

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120 Rockwell Automation Publication 1756-UM010C-EN-P - June 2021
Appendix C Module Schematics
Gate Inputs
Gate inputs are used for running prover and store count values. There is one
gate that is associated with each flowmeter input circuit (G0 corresponds to
F0).
Series A Module
To turn on a gate circuit, you must source current through the input resistors
sufficient to turn on the opto-isolator in the circuit. If no connection is made
to the pair of gate terminals, no current flows through the photodiode of the
opto-isolator and that gate is OFF (the corresponding input status indicator is
OFF).
The input current magnitude can be determined by:
IMPORTANT This schematic represents the Series A module
Z0 RET
Z1 RET
physical and electrical isolation
Z0 (5V)
Z1 (5V)
2
1
Input
6
5
RET
1 k 
R2
150 
R1
D1
D3
D2
Q1
R6 R7
C28
+5V
U2
C26
4
3
Z0 (12-24V)
Z1 (12-24V)
C27
Z0
Z1
CASE A – for 5V DC operation CASE B – for 10 V DC to 31.2 V DC operation
gate input current = (gate input voltage - 2V
1
)
150 
2
Examples
gate input current = (gate input voltage - 2V
1
)
1150 
2
1. There is approximately a 2V drop across (Q1 + the photodiode).
2. The operating range of the input is 5-10mA and Q1 functions as an overcurrent protection circuit. If an open collector
device with pull-up is used, the value of the pull-up must be added to the  value shown in the denominator.
gate input current = (5V- 2V)
150 
If gate input voltage = 5V DC
gate input current = 20 mA
Examples
gate input current = (10V- 2V)
1150 
2
If gate input voltage = 10V DC
gate input current = 7 mA
Examples
gate input current = (31.2V- 2V)
1150 
2
If gate input voltage = 31.2V DC
gate input current = 25.4 mA