Hardy Advantage HI LPRC03 Load Point - Manual (Page 16)

HI HLPRC03 SERIES LOAD POINT ASSEMBLY
Page 10
Electrical Tests for
Load Point
Assembly
Problems
Zero Balance
Test Problem: Changes in the Zero Balance.
Cause: Load Cell has been overloaded.
Remedy:
Step 1. Use a millivolt meter or the Integrated
Technician feature of the weighing instru-
ment and measure the signal output under
“no load” conditions. The reading should be
less than 1% of the full scale output.
NOTE: Output sensitivity can shift up to about 10% of their
full scale and still function correctly.
Step 2. If the output has shifted more than 10%,
replace the sensor.
Assumption: A 5VDC excitation on a sensor with a
3mV/V output sensitivity, a 1% shift in zero balance
will yield a .1mV/V change from the specification.
Bridge
Resistance
Test Problem: Changes in Bridge Resistance
Cause: Failure of a compensating element, or by a
broken or burned bridge wire. Often caused by an
electrical transient such as lightning or welding.
Remedy:
Step 1. Use an Ohmmeter and measure the resis-
tance between the EXC + and EXC- leads.
The value for the EXC leads should be 1106
ohms +/- 50 ohms.
Step 2. Use an Ohmmeter and measure the resis-
tance between the SIG + and SIG - leads.
The value for the SIG leads should be 1,000
ohms +/- 10 ohm.
Step 3. Readings that exceed the ranges indicated
suggest damage, and the load cell should be
throroughly inspected or replaced.