Measure loop current to ensure a device or distributed control system is sending the correct value. You can measure loop current from 0 to 25 mA on a 4-20 mA current loop.
Note: Measurements are for reference purposes only. Do not make critical process-control decisions based on these measurements.
Warning: Do not connect the mA terminals on the Trex unit to a power supply that is not current limited to 250 mA. This can blow a fuse inside the Trex unit. The repair/replacement will need to be completed at an authorized service center.
Warning: Do not connect the mA terminals (ammeter) in parallel with a powered 4-20 mA current loop. Ammeters have low resistance. This can disrupt the loop and cause devices to report incorrect values or positioners to move unexpectedly.
Connect the lead set to the
mA terminals on the Trex unit and to a
connection point on the loop.
The Trex unit can be connected at various point along the loop to measure current.
Example connection for measuring current
- Analog output.
- In the Loop Diagnostics application, view the measured current at the top of the screen.