Martel Electronics DMC1410 User Manual

Page 27

5.2 Measuring current with loop power

To test a 2-wire, loop powered transmitter that is disconnected from
wiring, use the loop power function. This function activates a 24V
supply in series with the current measuring circuit. To use this option
proceed as follows:
1. Select [mA LOOP] as primary parameter in the upper display.
2. Connect the calibrator to transmitter current loop terminals, as

shown in Figure 17.

Figure 17. Connection Using Current Loop

5.2-1 HART™ Resistor Selection
The DMC1410 can be set-up so that the 250 ohm resistor required
for HART™ configuration devices resides inside the DMC1410.
Enabling the DMC1410's internal 250 ohm resistor eliminates the
need to manually add a series resistor during a HART™ calibration
process.
NOTE: When the DMC1410's internal 250 resistor is enabled,

maximum load driving capability drops from 1000 ohms @ 20mA to
750 ohms @20mA.

Enable/Disable Procedure

1. Remove the battery cover and remove the 2 screws that are

at the top of the case.

2. Remove the 2 screws on the bottom or lower portion of the

case.