Rice Lake RoughDeck LP, Installation Manual

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RoughDeck LP
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3.0 Calibration
3.1 Corner Correction
All assembled RoughDeck LP scales are delivered with the junction box corner-trimmed. Corner trimming is only necessary
after replacing a load cell. To calibrate the scale, the output from each load cell must be matched by adjusting the signals with
potentiometers at the junction box. This process is known as trimming. Perform the following to complete corner correction:
1. Remove four hex screws from the junction box access cover. Retain screws for reuse.
2. Pull panel away from frame to remove.
3. Remove six Philips screws from the junction box cover. Retain screws for reuse.
4. Pull junction box cover away from the frame to remove.
5. Identify the load cell terminals corresponding to each corner (for example, CELL 1, CELL 2, CELL 3 and CELL 4)
( Figure 3-1 .)
Figure 3-1. Junction Box Terminal Blocks with Load Cell Connectors and Potentiometers Identified
6. Connect the indicator and calibrate using a test weight. The recommended test weight for RoughDeck LP models is
500 lb (226.80 kg), 25% of 2000 lb (907.20 kg) full scale.
7. Ensure there is no weight on the scale and zero the indicator.
8. Turn each of the four potentiometers clockwise to increase the reading until there is a clicking sound. This ensures the
maximum signal from each load cell ( Figure 3-1 ).
9. With all potentiometers at full signal, place the test weight on one corner and record the indicated weight.
10. Repeat the process for each of the other three corners.
11. Use the corner with the smallest output as a reference. Place the test weight on one of the other three corners and
adjust that cell's potentiometer to match the output of the reference cell.
12. Repeat this procedure with the other two high output corners.
13. Adjustments are interactive, so adjusting the three higher output corners may affect the reference cell output. Re-zero
the indicator and repeat the test until all corners are within ± 1% of the test weight used.
JP4
JP 2
PT4
PT3
JP3
PT1
EXP
PT2
JP1
1
CELL4
1
CELL1
1
CELL3
1
CELL2
IND
-EX
-SI
SHD
+SI
+EX
M
R
N
I
-SI
S2C
I
A
G
+EX
+SI
-SI
SHD
-EX
I
S
G
A
L
T
+SI
M
S
I
N
L
T
R
+EX
-EX
-SI
SHD
+SI
+EX
+SI
-EX
-SI
SHD
-EX
SHD
+SE
-SE
+EX
CELL 4 CELL 3
CELL 2 CELL 1
Potentiometers
Potentiometers