Hardy HI 2204LT Weight Transmitter - Manual (Page 13)

HI 2201LT/HI 2204LT
9
Step 2. Install a milli ammeter, in series, into the
output/power loop of the transmitter. If a
voltmeter is to be used for measurements,
and a resistor for calibration is not already
installed in the system, install a 100 ohm,
+- 0.1%, 1/4 W resistor, in series, into the
output/power loop of the transmitter. Volt-
meter readings are show in parentheses.
Step 3. If a voltmeter is used, attach the voltmeter
across the 100 ohm resistor.
Step 4. Adjust the transmitter FINE control for a 4
ma (1/4 V) reading on the meter. If neces-
sary, center the FINE control, and adjust
COARSE control first.
Step 5. Place a know weight on the scale. If possi-
ble, use a full scale weight for best results.
Step 6. Adjust the SPAN for 20 ma (2V) for full-
scale.
• Divide: Calibration Weight/Full-
Scale
Weight = (F)raction of full scale.
• Multiply: (F) (16 ma) = 1, the cur-
rent caused by the calibration
weight.
• Add: 1 + 4 ma = Calibration Cur-
rent, 1c
• Adjust the SPAN to produce the
Calibration Current, 1c, in the out-
put/power loop.
Example Calibration Weight = 750 pounds
Full Scale Capacity = 1000 pounds
Adjust SPAN for:
(750/1000) (16 ma) + 4 ma = 1c
(0.75) (16 ma) + 4 ma = 1c
12 ma + 4 ma = 1c
16 ma = 1c