Rice Lake AutoLift HE Low-Profile Lift - Manual (Page 13)

Adjustments and Calibration 9
3.0 Adjustments and Calibration
3.1 Mechanical Adjustments
To accommodate minor unevenness, adjust scale height up or down a fraction of an inch using the scale feet. Lift
the scale corner slightly and adjust the feet by hand until all feet are contacting corner pads equally.
The scale kit does not supply jam nuts for locking the feet, as there is a slight decrease in accuracy when the
jam nuts are tightened. If your application requires jam nuts to secure the feet, you can add them. You must
unscrew the feet beyond the minimum height to allow room for the jam nuts between the foot pads and the
load cells.
When adjusting scale feet, use care to prevent scale foot from bottoming out against the underside of the
load cell. Also, the foot stem may be damaged by bending or stripping threads if extended beyond the
maximum height adjustment.
After you complete any height adjustments, recheck the levelness of the deck with a spirit level. The deck must be
level within
1
/
4
".
3.2 Corner Correction
To calibrate the scale, adjust all four load cells so their output signals are equal. Adjust the signals using the poten-
tiometers at the junction box—a process known as trimming.
Remove the junction box cover and identify the load cell terminals corresponding to each corner (labeled CELL 1,
CELL 2, CELL 3, and CELL 4). See Figure 2-1 on page 7 for scale deck corner numbering.
Connect the indicator and calibrate using a test weight. The recommended test weight for all RoughDeck models is
25% of scale capacity: for example, 500 lbs for 2K-lb models.
With no weight on the scale, zero the indicator, then turn each of the four potentiometers (shaded areas of Figure 3-
1) clockwise to increase the reading until you hear a clicking sound. This ensures the maximum signal from each
load cell.
With all potentiometers at full signal, place the test weight on one corner and record the indicated weight. Repeat
the process for each of the other three corners.
Figure 3-1. Trim Potentiometers.
Next, 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. Repeat this procedure with the other two high corners.
Adjustments are somewhat interactive; adjusting the three higher outputs may affect the reference cell output, espe-
cially in smaller scale decks. Rezero the indicator and repeat the test until all corners are within ±.1% of the test
weight you are using.
Note
CAUTION
CELL 1
CELL 4
CELL 2
CELL 3
INDICATOR
+EX
–EX
+SI
–SI
100 K
+SE
–SE
+EX
+EX +EX
+EX
–EX
–EX –EX
–EX +SI
+SI +SI
+SI
–SI
–SI
–SI
–SI SHD
SHD
SHD
SHD
23126
Rev. A
SHD
JU1 JU2
JU3 JU4
100 K
100 K 100 K