Loop Power Test (789 Only) - Fluke ProcessMeter 789 Calibration Manual

789/787B
Calibration Manual

Loop Power Test (789 only)

1. Enable the dc volts autorange function of the multimeter.
2. Turn the rotary knob of the UUT to LOOP POWER.
3. Measure the open circuit voltage of the UUT and verify it is >29.2 V and <32 V.
4. Press J (BLUE) on the UUT to enable the 250 Ω HART resistor.
5. Repeat step 3.
6. Disable the 250 Ω HART resistor by pressing J (BLUE).
7. Connect the 1-kΩ shunt across SOURCE + and SOURCE - of the UUT.
8. Measure the loaded down voltage and verify it is >23.8 V and <32 V, see Figure 2.
9. Remove the 1-kΩ shunt.
10. Disconnect the UUT from the multimeter and turn the UUT off.
11. Select the dc current function on the multimeter and set it to the 1-amp range (a 0.1
12. Connect the current input terminals of the multimeter to the SOURCE + and
13. Turn the rotary knob of the UUT to LOOP POWER.
14. Verify the short circuit current is >24 mA and <35 mA.
789
100% MIN MAX
0%
14
Ω shunt is used in the 1-amp range).
SOURCE - terminals of the UUT.
UUT
PROCESSMETER
RANGE HOLD
REL
Hz
Figure 2. Verifying Loop Power
adm006F.EPS