Meriam MFT 4010 Modular Calibrator_HART Communicator - Manual (Page 92)

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2.0 Loop Power Application
The VMA will provide 24VDC Loop Power for transmitter loop circuits. The recommended wiring is depicted in
the diagram below:
Diagram 2.1 – Loop Power Connection Diagram for simple low load loop
Connect the test circuit according to the Diagram 2.1.
Include 250-ohm resistor for low load loops.
The loop power is turned on from the MFT
Measure Mode by pressing the following keys:
Press the More Soft Key two times
Press the Pon Soft Key to turn VMA power supply on
The SX sensor location (depending which bay the VMA is located in) should read approximately 24.00 VDC. The
MFT’s IV value will read the loop current.
To establish HART communications with the test device, press the MFT’s
HART key.
VOLTS
COM
mA
MFT
HART
Transmitter
VMA
Module
-
+
-
+
MFT
mA/V Meter
Measure
S1: 24.00 V
S2: 0.000 PSIG
S3: 72.05 deg F
IV: 4.000 mA
Pon Poff Vrng More