Rice Lake JB1010ST Signal Trim - Manual

Ten-Channel Signal Trim Junction Box
Installation
Manual
JB1010ST
Trimming Procedure
Trimming is a process of equalizing the output from multiple individual
load cells, or from pairs of cells if using the section trim format. When
all errors except cell mismatch and cable extensions or reductions have
been corrected, continue with the trimming procedure below.
1. Set all potentiometers fully counter-clockwise to give maximum
signal output from each cell.
2. Make sure isolation resistors corresponding to any unused termi-
nals have been cut to disable use of these channels.
3. Zero the indicator and place calibrated test weights over each load
cell in turn (or over each section) without allowing the weights to
overhang the sides. The amount of test weights used depends on
the scale configuration; for specific recommendations, refer to
Handbook 44 Field Manual, published by the Institute for Weights
and Measures. For a four-cell platform, we recommend using
25% of scale capacity.
4. Record the value each time weight is placed on the scale and allow
the scale to return to zero to check for friction or other mechanical
problems. Select the load cell or section which has the lowest
value as your reference point—this cell or section will not be
trimmed.
5. Now replace the same test load over each cell or section and trim
each with its potentiometer down to the reference level cell or
section. As corner corrections are somewhat interactive, check all
cells or sections again for repeatability.
6. Tighten all wiring connections. Pull excess cable out of the
enclosure and tighten the cord grip assemblies with a wrench. To
be watertight, each cord grip must be tightened so the rubber
sleeve begins to protrude from the hub.
7. Unused hubs must be plugged to prevent moisture entry. See the
Electronic Replacement Parts and Components catalog to order
extra hole plugs.
8. Insert a commercial desiccant containing antioxidant properties
into the junction box before closing. If the enclosure is in a damp
or wet area, change the desiccant every four to six months.
9. Replace the cover and tighten the cover screws in an alternating
pattern to be certain the gasket is compressed equally in all
locations.
TRIMMING
Whenever a substantial
amount of trim is necessary
to equalize output (more
than 5% of normal output),
check for other possible
problems. The best trim is
always the least amount of
trim.
TEST WEIGHTS
CAUTION: When loading
the corners, do not exceed
the concentrated load
capacity (CLC) specified by
the scale manufacturer.
CAUTION: To prevent water
and other contaminants
from entering the J-Box, fill
any unused cable grips with
post screw plugs, part
number 19538.
POST SCREW
PLUGS
If cables will be exposed to
water or other liquids, bend
a short downward loop in all
cables near the cord grips
so any fluids draining down
the cables will drip off
before reaching the junction
box.
CABLE DRIP LOOPS
3 68812
Authorized distributors and their employees
can view or download this manual from the
Rice Lake Weighing Systems distributor site
at
www.rlws.com.