Rice Lake Benchmark LP User manual

104742
Benchmark LP
Low-Profile Bench Scale
Installation Manual
TM

Contents
Contents ................................................................................................................................................... i
About This Manual ................................................................................................................................... 1
1.0 Introduction.................................................................................................................................. 1
2.0 Installation ................................................................................................................................... 2
2.1 Site Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.2 Unpacking and Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.3 Summing Board Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.4 Electrical Interface to Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.0 Adjustments and Calibration ....................................................................................................... 5
3.1 Mechanical Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2 Corner Correction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.3 Calibration Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.0 Service Information ..................................................................................................................... 7
4.1 Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.2 Periodic Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.3 Load Cell Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.3.1 Load Cell Wiring to Summing Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.4 Replacement Load Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Benchmark LP Limited Warranty............................................................................................................. 9
© 2008 Rice Lake Weighing Systems. All rights reserved. Printed in the United States of America.
Specifications subject to change without notice.
April 2008
Technical training seminarsare available through Rice Lake Weighing Systems.
Course descriptionsand datescan be viewed at www.ricelake.com or obtained by
calling 715-234-9171 and asking for the training department.

ii Benchmark LP Manual

Introduction 1
About This Manual
This manual is intended for use by service technicians
responsible for installing and servicing the
Benchmark™LP low-profile bench scale.
Warning
Some procedures described in this
manual require work inside the summing
board enclosure. These procedures are
to be performed by qualified service
personnel only.
Authorized distributors and their employees
can view or download this manual from the
Rice Lake Weighing Systems distributor
site at www.ricelake.com.
1.0 Introduction
The Benchmark LP is a four-cell, low-profile scale.
Features include:
• Available in sizes from 18 in. x 18 in (.46 m x
46 m) to 36 in x 36 in (.91 m x .91 m).
• Capacities from 100 to 1000 lbs (45 - 453 kg).
• Fully electronic low-profile load receivers.
• Four corner-mounted, FM-approved planar
beam load cells.
• Signal-trim summing board for any necessary
corner corrections, mounted under a stainless
steel cover that can be sealed for
legal-for-trade.
• All models come pre-trimmed; corner
corrections should not be necessary.
• Load cell cables are held down with
replaceable cable ties near each corner.
• Adjustable feet can be used to allow leveling
of the scale to compensate for minor floor
irregularities.
• Holes are located in the lower frame to be
used for permanent mounting applications.
Model Designations
The model identification label is located on the side of
the frame. Include both model number and serial
number when ordering replacement parts.
Electrical Grounding
For systems where the scale is connected to a 115
VAC circuit, the indicator must be directly connected
to an earth ground with a ground interface cable of no
more than 3Ωresistance throughout its length.
Load Cells
• Four (4) Rice Lake RLBLP (planar beam)
• Rated Excitation: 5-15 VDC
Grade Level Requirement
The supporting surface of the scale (encompassing
four feet) must be level within 1/4in of horizontal.
End Load Capacity
60% of full scale capacity.
Platform Dimensions, Capacity, and Torque Specs
Table 1-1. Platform dimensions and capacity
*Non-NTEP
Part Number Capacity Platform Dimensions (LxWxH) To r qu e To
97662 100 lbs. 18” x 18” x 1.67” (2.63“ with leveling feet) 50 LBSPER IN
97663 250 lbs. 18” x 18” x 1.74” (2.50“ with leveling feet) 125 LBSPER IN
97664 500 lbs. 18” x 18” x 1.93” (2.69“ with leveling feet) 125 LBSPER IN
97665 100 lbs. 24” x 24” x 1.69” (2.66“ with leveling feet) 50 LBSPER IN
97666 250 lbs. 24” x 24” x 2.07” (2.83“ with leveling feet) 125 LBSPER IN
97667 500 lbs. 24” x 24” x 2.26” (3.02“ with leveling feet) 125 LBSPER IN
97668 500 lbs. 30” x 30” x 2.26” (3.02“ with leveling feet) 125 LBSPER IN
97669* 1000 lbs. 30” x 30” x 2.70” (3.47“ with leveling feet) 20 LBSPER FT
97670 500 lbs. 36” x 36” x 2.26” (3.02“ with leveling feet) 125 LBSPER IN
97671* 1000 lbs. 36” x 36” x 2.70” (3.47“ with leveling feet) 20 LBSPER FT

2Benchmark LP Manual
2.0 Installation
Standard installation of the Benchmark™LP floor scale consists of the following steps:
• Select a site
• Check levelness and smoothness of site
• Unpack scale
• Adjust the four feet on the scale
• Connect cable to summing board and
indicator
• Calibrate the unit
2.1 Site Preparation
The scale must not be loaded beyond its capacity, even momentarily. Do not select a site where overweight loads
would have to maneuver to avoid crossing the platform. Avoid areas where the scale might receive damaging
side impacts from wheels or forklift tines, or shock damage from falling objects. Avoid areas where water may
damage the scale.
The interface cable between the scale and the indicator must be protected against crushing, cutting, or moisture
damage. If the chosen site has such potential dangers, some method of protection, such as running the cable in
conduit, will be necessary.
In operation, the scale must be level within 1/4inch. Either choose a site where the floor is close to this standard
to avoid excessive shimming, or modify the floor at the chosen site to meet this standard.
2.2 Unpacking and Assembly
1. Remove all packing material and inspect scale for visible damage caused during shipment.
2. Remove the four overload stops on the underside of the scale, shown in Figure 2-1.
Overload
Stops
Overload
Stops
Figure 2-1. Overload Stops to be Removed (4)
3. Remove the black scale cover.
4. Remove the summing board cover in the center of the scale.
5. Wire the homerun cable. Refer to instructions in Section 2.3 on page 3.
6. Properly secure the cable with nylon ties (supplied).
7. Using the bubble level next to the summing board, ensure the scale is level.
8. Replace the black scale cover and use the four mounting screws to secure it in place.
9. If necessary, perform a corner correction. See Section 3.2 on page 5.
10. Replace the summing board cover.
11. Replace the black center cover.
12. Set the stainless steel cover on the scale.

Installation 3
2.3 Summing Board Security
After an NTEP inspector has examined the unit, he/she will install security cables on the summing board cover.
These cables prevent the summing board from being tampered with by an unauthorized individual. If these
cables are removed, NTEP Certification will become void.
Figure 2-2. Summing board cover with security cables installed
2.4 Electrical Interface to Indicator
Twenty feet of 6-wire cable to connect the scale to the weight indicator is supplied with each scale. Both ends
have the wires stripped and tinned.
To access the summing board,
1. Remove the stainless steel platform.
2. Remove lid in the center of the platform, revealing the summing board coverplate.
3. Remove security cables (this will void NTEP Certification).
4. Remove screws on the summing board coverplate and remove lid.
Wire Connections
Remove the summing board cover and connect the wires to the INDICATOR terminal (Figure 2-3). To connect
the indicator wires to the appropriate connectors, push in the quick connect lever with a small screwdriver or
ballpoint pen. When holding the lever, insert the appropriate wire into the exposed wire opening.
JP4
JP2
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
Figure 2-3. Summing board indicator terminal

4Benchmark LP Manual
Cable Routing
The cable must be routed to the indicator in a manner that will protect the cable from damage. When planning
cable routing, leave a loose coil of excess cable under the scale to facilitate future lifting of the scale for servicing
or cleaning.
1. When the interface cable is protected and in its final position, complete connections to the indicator. See
indicator installation manual for wiring information.
2. If necessary, trim corners as described in Section 3.2 on page 5.
3. Check all strain relief for tightness.
Figure 2-4. Homerun cable wired to summing board and secured with nylon ties

Adjustments and Calibration 5
3.0 Adjustments and Calibration
3.1 Mechanical Adjustments
To accommodate minor floor unevenness, scale feet can be used to adjust scale height up or down a fraction of an
inch. Adjust the feet by hand (lift the scale corner slightly with a pry bar) until all feet are contacting the floor
equally. Jam nuts are supplied for locking the feet in place.
When height adjustments are complete, recheck level of the deck with a spirit level. The deck must be level
within 1/4".
3.2 Corner Correction
All assembled Benchmark™LP scales are delivered with the summing board 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 summing board—a process known as trimming.
1. Remove the summing board cover and identify the correct load cell terminal corresponding to each
corner (labeled CELL 1, CELL 2, and so on). See Figure 4-3 on page 8 for scale deck corner numbering.
2. The indicator must be connected and calibrated approximately, but it need not indicate the exact weight
value. A test weight will be required. The recommended test weight for all Benchmark™LP models is
25% of scale capacity: for example, 25 lbs for 100-lb models, 250 lbs for 1000-lb models.
3. With no weight on the scale, zero the indicator.
4. Turn all four potentiometers fully clockwise (shaded areas of Figure 3-1) to increase the reading until a
clicking sound is heard from each potentiometer. This ensures the maximum signal from each load cell.
JP4
JP2
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
Potentiometers
Jumper Locations
JP1 and JP2
Shaded
Jumper Locations
JP3 and JP4
Shaded
Potentiometers
Figure 3-1. Trim Potentiometers
5. Zero the indicator and place 25% of scale capacity using calibrated test weights over each load cell in
turn.
6. Record the value displayed on the indicator after the test weight is placed in turn on each corner (directly
over the load cell) without allowing the weight to overhang the sides. Allow the scale to return to zero
each time to check for friction or other mechanical problems. Select the load cell which has the lowest
value as your reference point. This cell will not be trimmed.
7. Replace the same test load over each cell in turn. Using the corresponding potentiometer, trim each cell
down to equal the reference load cell. As corner corrections are somewhat interactive, check all cells
again for repeatability. If necessary, repeat steps 5 and 6.

6Benchmark LP Manual
3.3 Calibration Procedure
Refer to the indicator manual to determine correct calibration procedures.
It is recommended that the scale be "exercised" before calibration to be certain that everything is seated.
1. Load the scale to near capacity two or three times.
2. With no load on the scale, place the indicator in its calibration mode and perform a zero calibration.
3. Place test weights on the platform not exceeding the scale's full capacity. If several weights are used,
they should be evenly distributed around the platform.
4. Perform a span calibration.