Fairbanks H90-5200-A Digital Instrument - Manual (Page 34)

J. Programming the SMART 4-20mA
1. Install Accessory 148. See Appendix VI for instructions.
2. Place a 100 ohm, 0.1% sense resistor (Part #510381) in series with the loop.
Place a DVM across the shunt resistor to monitor the current.
(4-20mA = 0.400 to 2.000V)
NOTE: The Accessory can be configured for voltage outputs by placing a shunt
resistor at the output terminal block.
Example: To convert 4-20mA to 1-5VDC use a 250 Ohm resistor. To convert 0-
20mA to 0- 10 VDC use a 500 Ohm resistor.
3. Press FUNC, 2 keys to enter the 4-20mA setup menu. The display will read 4-20
x’,where x equals 0,1, or 2. Select “0” to disable the 4-20mA output. Select “1” to set
the 4-20mA output to correspond to GROSS weight. Select “2’ to set the 4-20mA
output to correspond to NET weight. Press the ENTER key.
4. The display will now flash “LoLooP” for 1 second and then show “ACxxxx” (Analog
Count), where “xxxx” is a number between 0 and 4095. This number corresponds to
the Low Loop current calibration point, typically 4mA. Use the arrow keys to scroll
UP or DOWN until the Analog output reaches the low loop current output equal to
the desired value as monitored on the DVM. Press ENTER to store the value.
5. The display will now flash the weight that corresponds to the low loop current
calibration. Enter a new weight with the keypad if desired, and then press ENTER.
6. Repeat steps 4 and 5 for the Hi Loop, typically 20mA calibration.
7. The display will now return to the normal weigh mode. As long as the instrument is
monitoring the weight, the 4-20mA output will be updated every A/D cycle.
EXAMPLES:
a. To calibrate the 4-20mA loop to correspond to 0-130 lb NET, a typical
50515 34 Issue #2 4/04
▲
▲
mA
0
20mA
LBS NET
4mA
2431
OUTPUT
130