Martel Electronics DMC1400 - Manual (Page 21)

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4.3-1 HART™ Resistor Selection
The DMC1400 can be set-up so that the 250 ohm resistor required
for HART™ configuration devices resides inside the DMC1400.
Enabling the DMC1400's internal 250 ohm resistor eliminates the
need to manually add a series resistor during a HART™ calibration
process.
NOTE: When the DMC1400'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.
3. Gently remove the top half of the case from the bottom.
4. Figure 10a. shows the location of the HART™ jumpers.
Figure 10a.
4.4 Simulating a Transmitter
To have the calibrator supply a variable test current to a loop in place
of a transmitter, follow these steps:
1. Select lower display from the Main Menu.