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Operation and Wiring
Standard Wiring
The Model 640/641/645/646 B7 Series uses plug-in type screw terminal connectors for all input and output
connections and operate from a standard 2-wire, 4-20mA loop. Attach the positive (+) input from the power supply
to Pin 2 and the negative (-) input from the power supply to Pin 3.
Figure 1
– wiring: standard connection
Figure 2
– wiring: loop powered
Figure 3
– wiring: loop powered/DC source
If using a standard DC power supply, install either an ammeter and/or load resistor in line with the return
connection Pin 3.
The resistor will generate a DC voltage that is proportional to current by:
V = IR
If R = 500
and I = 6mA, then V = 3Vdc
Note:
