CHAPTER 6
89
6.2
LOAD CELL EVALUATION TESTS
The tests listed below will help identify and locate any problem you may encounter with your Vulcan
load cells.
Leakage Test
Tare Test
Resistance Test
6.2.1 LEAKAGE
TEST
PROCEDURE
Required Equipment: Digital Multi-Meter With Conductivity Scale
Isopropyl
Alcohol
Cotton
Swabs
Hair
Dryer
Optional Equipment:
Vulcan Check-Out Box
The Leakage Test Procedure detects the presence of moisture that could cause erratic meter readings.
The way to measure leakage is to use a digital multi-meter that has a conductivity scale. Electrical
isolation is measured between any pin and an unpainted clean surface on the load cell or the connector
body. Electrical isolation must not exceed 2.0 nS (nano-siemans) or be less than 500 Meg Ohms.
Refer to Figure 6-B for the Leakage Test equipment setup. If a Vulcan Check-Out Box is used, it is
important that the VSL Vulcoder leads from the load cells of the channel being tested are
disconnected.
For proper operation, the power and signal leads from the load cell must have a very high resistance to
the load cell body. An electrical path between the wires and the body would indicate moisture in the
cell or shorting to the body. This would result in erratic, fluctuating, or even out of range weight
displays.
If the load cell fails (electrical isolation is greater than 2.0 nS or is less that 500 Meg Ohms), check the
inside of the load cell connector with a dry cotton swab to make sure it is clean and dry. If not, clean
with isopropyl alcohol, dry with a hair dryer, and check the electrical isolation again.
If the load cell cannot be brought to Vulcan specifications, contact your Vulcan dealer.
June 21, 2006
VULCAN ON-BOARD SCALES 1-800-237-0022
Doc. 44-10032-001 Rev. C
©
STRESS-TEK, INC. 2006
