OHAUS Valor 1000W, Service Manual

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CHAPTER 2 DIAGNOSTIC GUIDE
Valor
™ 1000W Series Service Manual
2-3 Ohaus Corporation www.ohaus.com
2.2.2 Checking Load Cells for Trouble
Figure 2-1. Load Cell wire connections to Main PCB.
CAUTION:
IN THE NEXT STEP, DO NOT OVERLOAD THE SCALE BEYOND FULL
CAPACITY RATING.
– Measure the voltages on IN- and IN+ wires, disconnected from PCB
(points 1 and 2 in Figure 2-1). Note: Measurements must be made with these
wires disconnected from the PCB. These measurements represent the output of
the Load Cell. Record measurements at Zero Load, 50% and full scale
capacities. See Table 2-3 for typical readings.
NOTE : Table 2-3 indicates typical readings. Actual values can vary, but should
remain linear throughout the range. If readings are out of tolerance, replace the
Load cell. (See Section 3.6.)
TABLE 2-3. LOAD CELL OUTPUT READINGS (in mV with 5V Excitation)
Model/Capacity Zero Load 50% Load 100% Load
V11PW3 / 3kg 1.5 ± 2.0 Zero + 4.1 Zero + 6.7
V11PW6 / 6kg
0.9 ± 2.0 Zero + 3.4 Zero + 5.9
V11PW15 / 15kg
0.6 ± 2.0 Zero ± 3.2 Zero ± 5.9
V11PW30 / 30kg 0.3 ± 2.0 Zero + 2.8 Zero + 5.4