Hardy HI HLPT Tension Load Points - Manual (Page 15)

OPERATION AND INSTALLATION MANUAL
Page 9
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 cause by an elec-
trical transient such as lightning.
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 + - 5
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 + - 1
ohm.
Step 3. Readings that exceed the ranges indicated
suggest damage and the load cell should
be throroughly inspected or replaced.
Resistance to
Ground Test
Problem:Electrical leakage is creating an
unstable output from the instru-
ment.
Cause: Water contamination in the load
sensors or cables.
Remedy:
Step 1. Tie together the load sensor excitation (2),
signal (2) and ground (1) wires.
NOTE: Be careful NOT to include the two C2 wires.