Ametek TM2000 Pro, User Manual

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Current Outputs: Other Applications | C-1
Current Outputs: Other AppliCAtiOns
This appendix describes how to:
• Modulate external power loop using current outputs.
• Power current outputs from an external power supply.
powering Current Outputs from an external power supply
The Series 2000 control unit wiring card contains a set of terminals that can be
used to connect an external voltage source to power the standard current outputs:
VEXT1,2 +
VEXT1,2 ‑
Jumper JP2 on the Series 2000 control unit display module is used to define which
power source to use. If there is a JP2 jumper (factory default), the control unit uses
the internal supply to power the current output circuits. If you try to use an external
voltage at this time, the system will use whichever voltage is higher ‑ control unit
voltage is normally about 28 Volts. If the JP2 jumper is removed, the external volt ‑
age source must be used to power the current output circuits. The external voltage
source must be no greater than 30 VDC. See the “Option Card Installation” section
in Chapter 3 for information on how to access or remove the display module.
To determine the minimum external voltage supply required to power the current
outputs, use the following formula:
VEXTmin = .02 amps (RLoad + Rwires) + 4 volt
where:
VEXTmin
= the minimum external voltage required to power current output
circuit
RLoad
= the load resistance of the current output device
Rwires
= the resistance of the wires