I. HANDLING AND STORAGE ............................................................................................................... 1
Inspection And Handling
Disposal And Recycling
Storage
II. GENERAL SAFETY ............................................................................................................................. 2
Authorized Personnel
Use
Misuse
III. PRODUCT DESCRIPTION ................................................................................................................. 3
Function
Features
Technical Specications
IV. MECHANICAL INSTALLATION ........................................................................................................... 5
Vessel Preparation
General Requirements
Hardware And Bolts
Leveling The Vessel
V. ELECTRICAL INSTALLATION .......................................................................................................... 12
General Safety
Disconnect Requirements For Permanently Installed Equipment
Installation
Guidelines
VI. SET-UP ............................................................................................................................................. 16
Installing A Sun Shield
Calibration
Live Load Calibration
Adding Material
Removing Material
Manual Calibration
VII. TROUBLESHOOTING ...................................................................................................................... 20
VIII. DIMENSIONAL DRAWINGS ............................................................................................................. 23
Page 4
SAFETY SYMBOLS
WARNING:
IDENTIFIES CONDITIONS OR PROCEDURES, WHICH IF NOT FOLLOWED, COULD
RESULT IN SERIOUS INJURY. RISK OF ELECTRICAL SHOCK.
CAUTION:
IDENTIFIES CONDITIONS OR PROCEDURES, WHICH IF NOT FOLLOWED, COULD
RESULT IN SERIOUS DAMAGE OR FAILURE OF THE EQUIPMENT.
Page 5
Load Stand® II
Installation & Operation Manual
I. HANDLING AND STORAGE
SAVE THESE INSTRUCTIONS
INSPECTION AND HANDLING
Do not dispose of the carton or packing materials.
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Each package should be inspected upon receipt for damage that may have occurred due to mishandling during
shipping. If the unit is received damaged, notify the carrier or the factory for instructions. Failure to do so may
void your warranty. If you have any problems or questions, consult Customer Support at 800-426-9010.
DISPOSAL AND RECYCLING
This product can be recycled by specialized companies and must not be disposed of in a municipal collection
site. If you do not have the means to dispose of properly, please contact for return and disposal instructions or
options.
STORAGE
If the device is not scheduled for immediate installation following delivery, the following steps should be
observed:
1. Following inspection, repackage the unit into its original packaging.
2. Select a clean dry site, free of vibration, shock and impact hazards.
3. If storage will be extended longer than 30 days, the unit must be stored at temperatures between
32º and 104º F (0º to 40° C) in non-condensing atmosphere with humidity less than 85%.
CAUTION: DO NOT STORE A NON-POWERED UNIT OUTDOORS FOR A PROLONGED PERIOD.
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II. GENERAL SAFETY
AUTHORIZED PERSONNEL
All instructions described in the document must be performed by authorized and qualied service personnel
only. Before installing the unit, please read these instructions and familiarize yourself with the requirements and
functions of the device. The required personal protective equipment must always be worn when servicing this
device.
USE
The device is solely intended for use as described in this manual. Reliable operation is ensured only if the
instrument is used according to the specications described in this document. For safety and warranty reasons,
use of accessory equipment not recommended by the manufacturer or modication of this device is explicitly
forbidden. All servicing of this equipment must be performed by qualied service personnel only. This device
should be mounted in locations where it will not be subject to tampering by unauthorized personnel.
MISUSE
Improper use or installation of this device may cause the following:
• Personal injury or harm
• Application specic hazards such as vessel overll
• Damage to the device or system
If any questions or problems arise during installation of this equipment, please contact Customer Support at
800-426-9010.
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III. PRODUCT DESCRIPTION
FUNCTION
The Kistler-Morse Load Stand® II is a direct vessel-to-foundation structural member designed to be your
dependable and accurate continuous inventory monitoring and control solution. The Load Stand II system
is ideal for vessels with loads of 100,000 lbs (45,000 kg) or more and is available for loads of 25,000 to
1,000,000 lbs (11,000 to 453,000 kg) per support point.
The monolithic design becomes an integral part of the vessel structure for maintenance free weight
measurements. The sensing elements are eld replaceable without taking the vessel out of service.
The mechanical design of the Load Stand II lends to simplied design of the mounting, whether by legs
or gussets. Simple, rugged, and easy to match end-mounting plates yield minimum design time and easy
installations.
FEATURES
• Monolithic Design
• High Output
• Multiple Weight Ranges
• Solid State Strain Sensors
• Limited Down Time
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TECHNICAL SPECIFICATIONS
FUNCTIONAL
Excitation Voltage - Operating Range12 VDC - 30 VDC
Current Draw15.52 mA (70º F, 21º C)
Power Consumption186.4 mW (70º F, 21º C) at 12 VDC excitation
UBC Allowed Frame and Bolt LoadsRefer to Table
Ultimate Frame and Bolt Design StrengthRefer to Table
Sensor Functional Integrity200% of rated load
PERFORMANCE
Rated Output320 mV or 26.6 mV/V @ 12 V Excitation
No Load Output± 50 mV
Non-Linearity & Hysteresis± 0.20% of rated output
Repeatability± 0.10% of rated output
PHYSICAL
Temperature Range Operational: -30º to 150º F (-34º to 66º C); Unit remains operational, however, if the
Humidity100% Non-condensing
RatingDesigned for outdoor applications
PedestalASTM A53 GR B
FlangesASTM A36
Junction BoxABS with UV additive or 304 Stainless Steel
Resilient PadReinforced Rubber
FinishPolyester Powder Coat
SensorMicrocell II
Shipping WeightRefer to Table
temperature exceeds the compensated range, the unit may not perform to specications
Storage: -30º to 150º F (-34º to 66º C)
Compensated Std Temperature Range: 0º to 100º F (-18º to 38º C)
Compensated Mid Temperature Range: 50º to 150º F (10º to 66º C)
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IV. MECHANICAL INSTALLATION
WARNING: REMOVE POWER FROM THE UNIT BEFORE INSTALLING, REMOVING, OR MAKING
ADJUSTMENTS.
VESSEL PREPARATION
There are two aspects to successful use of Load Stands — properly functioning Load Stands and appropriate
vessel support characteristics. Review the following list of error sources, and make the recommended
corrections before you install Load Stands:
• An inadequate vessel foundation can allow excessive movement. Ensure the foundation is concrete or
steel.
• Hidden load-bearing structures, such as discharge chutes or plumbing supported by the oor, can
reduce loads on the vessel supports. Install exible couplings to minimize this problem.
• Cross-connecting structures, such as catwalks and manifolds, can transfer loads from adjacent vessels.
Install slip joint or ex couplings to minimize this problem.
• Shock loads can damage the Load Stand. Install protective barriers or stops to prevent vehicles from
hitting the vessel supports.
• Extra holes in the vessel gusset or vessel base plate which bolts to the Load Stand, replace the gusset/
plate with one with the correct number of holes for bolting to the Load Stand.
GENERAL REQUIREMENTS
When raising the vessel for Load Stand installation, use proper support to prevent the vessel from tipping or falling.
HARDWARE AND BOLTS
1. Kistler-Morse provides rubber washer assemblies for the Load Stand top mounting hole connections.
2. All other hardware to attach the Load Stand to the vessel and to the foundation is customer-supplied.
3. Use specied hardware and bolt sizes.
CAUTION: USING LARGER THAN SPECIFIED SIZES MAY OVERSTRESS THE LOAD STAND
DURING INSTALLATION, DAMAGING THE LOAD STAND AND VOIDING THE WARRANTY.
4. Use bolts with sufcient threaded length to accommodate the thickness of the connecting parts and the
specied nuts and washers. The length of the bolts should not be so long that they interfere with other
parts of the installation.
• Kistler-Morse recommends the placement of a base plate beneath the Load Stand. However, the
installation procedure and accompanying illustrations do not show a base plate.
• During installation, do not put the entire vessel load on less than the correct number of Load Stands.
• If you need to raise the vessel or one vessel leg after installation: Loosen the bolts on all the
Load Stands to prevent overloading.
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INSTALLATION
WARNING: USE PROPER SUPPORTS TO PREVENT THE VESSEL FROM TIPPING OR FALLING.
1. Raise the vessel.
2. Inspect the bottom of the vessel mounting surface to ensure it is perfectly at. Check for angular
misalignment. Remove any debris from the mounting surface.
3. Mount the Load Stands on the foundation.
a. Place the customer-supplied leveling nut and hardened washer on each anchor bolt. Check the
angular alignment.
b. Carefully place the Load Stand on the leveling nuts/washers, aligning the mounting holes with the
foundation anchor bolts.
c. Place the customer-supplied hardened washer and nut on each anchor bolt. Do not fully tighten the
nuts at this time. Leave a 1/4” (6 mm) gap between the nut and washer to allow for positioning the
Load Stand.
d. Place only the rubber pad on the top of the Load Stand, aligning the mounting holes.
e. Repeat Steps A through D for each Load Stand.
f. Record the no load output.
4. Mount the vessel on the Load Stands:
a. Slowly lower the vessel until it is resting on the Load Stand assemblies. Alignment pins may be used
to help guide and position the vessel.
b. Center the Load Stand top mounting holes with the vessel mounting holes, using the clearance
available from the Load Stand bottom mounting holes.
NOTE: On 50,000 lb (22,680 kg) or larger, Load Stands, a pry bar may be used at the base of the Load Stand
to gently move it into position.
CAUTION: IF THE VESSEL HOLE PATTERN DOES NOT MATCH UP WITH THE LOAD STAND HOLE
PATTERN, MODIFY THE MOUNTING HOLES ON THE VESSEL. DO NOT HAMMER THE LOAD
STAND INTO POSITION OR FORCE THE LOAD STAND INTO POSITION BY TIGHTENING THE
MOUNTING BOLTS.
c. Place a rubber washer on each customer-provided top bolt. Place the four top bolts through the
vessel, rubber pad, and Load Stand mounting holes.
d. Place a rubber washer and customer provided nut on the end of each bolt. Tighten the nuts nger
tight. Do not compress the rubber washers at this time.
5. Perform preliminary leveling:
a. Inspect the installation for gaps between the vessel mounting plate and the Load Stand.
b. Eliminate gaps by doing one or a combination of the following:
• Turn the leveling nuts, only to raise the entire load stand.
• Install one or more full shims above the Load Stand rubber pad. Two shims are provided by
Kistler-Morse with each Load Stand.
•
Install one or more partial shims above the Load Stand rubber pad. Two shims are provided by
Kistler-Morse with each Load Stand. Using the Load Stand ange as a guide, mark the required shim
shape on a thin piece of cardboard. Use this as a template to cut the required shape from a full shim.
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CAUTION: IF INSTALLING SHIMS, LOOSEN THE TOP BOLTS ON ALL THE LOAD STANDS BEFORE
RAISING THE VESSEL.
Leveling the vessel distributes the weight evenly on all the Load Stands, increasing system accuracy. Perform
this procedure while the vessel is still empty:
1. Check if Leveling Needed
a. Remove the junction box cover.
b.
Connect the red, white, and black wires of a 3-conductor cable to the corresponding terminals on TB1 of
the Load Stand junction box. Connect the other end of the cable to the corresponding terminals of the K-M
T
est Meter. Turn on the power to the Test Meter and set the Simulate/Test switch to the Test position.
NOTE: If a Kistler-Morse Test Meter is not available, before proceeding refer to Set-Up; Alternate Method for
Checking Output.
c. Verify the dead weight voltage output of the Load Stand from step 3f.
d. Calculate the change in output, as shown in the example. Output Change = uninstalled output
- installed output. The change in output must be positive.
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• Check the wiring polarity at the K-M Test Meter. Ensure the red, white, and black wires are connected to the
corresponding terminals.
• If the wiring is correct and you still observe a negative output change, the vessel may be tilted. Vessel tilting
shifts the load onto some Load Stands while putting other Load Stand(s) in a no load or tension load condition.
This can occur in cases of extreme thermal deformation or unequal vessel leg length. Proceed to Step 2 to level
the vessel.
e. Repeat Steps A through D for each Load Stand for this vessel.
f. Calculate the average output change for all Load Stands for this vessel. The output increase for each
Load Stand must be within ±25% of the average output increase. Load Stands 1, 2, and 4 meet this
requirement, while Load Stand 3 does not.
g. If the installation meets the criteria described above (change in output is positive and is within ±25%
of the average output increase), the vessel is sufciently level.
• If sufciently level, proceed to Step 3 to complete the installation.
• If not sufciently level, level the vessel as described in Step 2.
LOAD STAND STANDARDIZATION
SENSOR A SENSOR B SENSOR C SENSOR D
B W R B W R B W R B W R
TB3
B W R SHLD B W R
TB1 TB2
Junction Box PCB
KM Test Meter
Note: Wiring from sensors to
terminal TB3 not shown for
clarity.
SENSOR
ON
TEST
METER
OFF
SIMULATETEST
+EXSIGNAL-EX
ADJUST
Red White Black
Checking Output using Kistler-Morse Test Meter
Load Not Installed Installed Dead Weight Output Change (mV)Stand # Output (mV) Output (mV)
Allowable Range for Output Change = Average Output Change ± 25% = 48.25 ± (
All Load Stands meet the requirement that all output changes must be positive (+). Load Stands 1, 2, and 4 meet the
requirement that the output change be within ± 25% of the average output change. Load Stand 3 does not meet the
requirement, and its small output change indicates it is carrying much less weight than the other supports. The vessel
must be leveled to distribute the weight more evenly over all the supports.
(Installed - Not Installed)
1
/2 x 48.25) = 36.18 to 60.3
Example — Recording and Analysis of Output for Level Check
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2. Level the vessel.
CAUTION: LOOSEN THE TOP BOLTS ON ALL THE LOAD STANDS BEFORE RAISING THE VESSEL.
a. Raise the vessel legs for the low output load stands.
b. Raise or lower the leveling nuts or add shim(s) above the rubber pad as required adjusting the
distribution of weight on the Load Stands. Raising the leveling nuts and/or adding shims increases
the weight on the Load Stand. Lowering the leveling nuts decreases the weight on the Load Stand.
NOTE:
Adjusting leveling nuts and/or shimming on one Load Stand affects the weight distribution on all Load Stands.
c. Slowly lower the vessel leg onto the Load Stand assembly.
d. Repeat Step 1, rechecking the output of all the Load Stands and recalculating the Output Change
(dead weight output - no-load output).
e. Repeat Steps 2A through 2D until the installation meets the criteria for weight distribution.
3. Complete Installation: Once the vessel is level, complete the installation:
a. Tighten the nuts on the anchor bolts per the local code.
b. Verify readings.
c. Tighten the nuts on the upper bolts 1/2 turns past nger
tight. This will compress the rubber washers and rubber pad.
d. Apply threadlocker to the upper bolts and anchor bolts to
prevent loosening of the nuts.
e.
Pack grout or concrete under the Load Stand. Do not grout
ApplyThreadlocker
Tighten11/2turns
pastfingertight
TightenperUBC
Installgrout
above the bottom edge of the Load Stand assembly.
f. Replace the junction box cover if not ready to begin
wiring the junction boxes together and to the signal
processor, to ensure no moisture enters the box.
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FIGURE 1: LOAD STAND DIMENSION CHART (For any note references, see Figure 2 or 3)
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FIGURE 2: CONCRETE MOUNTING
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FIGURE 3: SUPPORT BEAM MOUNTING
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V. ELECTRICAL INSTALLATION
WARNING: VERY HIGH VOLTAGE IS PRESENT. REMOVE POWER FROM THE UNIT BEFORE
INSTALLING, REMOVING, OR MAKING ADJUSTMENTS
GENERAL SAFETY
When using electrical equipment, you should always follow basic safety precautions, including the following:
• The installation and wiring of this product must comply with all national, federal, state, municipal, and
local codes that apply.
• Properly ground the enclosure to an adequate earth ground.
•
Do not modify any factory wiring. Connections should only be made to the terminals described in this section.
• All connections to the unit must use conductors with an insulation rating of 300 V minimum, rated for
212º F (105º C), a minimum ammability rating of VW-1, and be of appropriate gauge for the voltage and
current required (see specications).
• Do not allow moisture to enter the electronics enclosure. Conduit should slope downward from the unit
housing. Install drip loops and seal conduit with silicone rubber product.
DISCONNECT REQUIREMENTS FOR PERMANENTLY INSTALLED EQUIPMENT
A dedicated disconnecting device (circuit breaker) must be provided for the proper installation of the unit. If
independent circuits are used for power input and main relay outputs, individual disconnects are required.
Disconnects must meet the following requirements:
• Located in close proximity to the device
• Easily accessible to the operator
• Appropriately marked as the disconnect for the device and associated circuit
• Sized appropriately to the requirements of the protected circuit (See specications)
INSTALLATION
There are two versions of the junction box enclosure. Both versions have four small holes, which were used for
factory-wiring the sensors to the junction box. In addition, the junction box has one or two large holes for wiring
the junction box to other junction boxes and the signal processor:
• One large hole (conduit installation); the large hole accommodates a 3/4” conduit tting.
• Two large holes (non-conduit installation); the two large holes are equipped with PG13.5 cable ttings.
K-M requires the use of cable trays for non-conduit installations.
GUIDELINES
• The procedure below assumes the conduit/cable tray has been installed.
• Seal all conduit ttings against water entry. Install drain holes at conduit/cable tray lowest elevation(s) to
allow condensation to drain.
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• Use Belden 3-conductor shielded interconnect cable or equivalent to wire junction boxes together and
to the signal processor, for lengths up to 2,000’ (305 m)
• When wiring cable to junction box terminals, strip back 3” (76 mm) of cable sheathing to expose the
three conductor wires and shield wire inside. Strip 1/4” (6 mm) of insulation from the end of each of the
conductor wires. Figure 3-7. Spread a generous bead of sealant around the sides of the PG 13.5 cable
ttings. Install the ttings in the two large holes.
CAUTION: ONLY USE SIKAFLEX 1A POLYURETHANE SEALANT OR DOW CORNING RTV 739 OR
RTV 738. OTHER SEALANTS MAY CONTAIN ACETIC ACID, WHICH IS HARMFUL TO SENSORS
AND ELECTRONICS.
1. See Figure 3-8 (conduit installation) or Figure 3-9 (non-conduit installation). Route the 3-conductor cable
through the tting into the junction box farthest from the signal processor. Connect wires from the cable
to the TB2 terminal in the junction box: black wire to B, white wire to W, and red wire to R. Connect the
cable shield wire to the Shield terminal between TB1 and TB2.
2. Route the cable through conduit/cable tray to the next junction box. Estimate the required length of
cable to the terminal strip, allowing a little extra for strain relief. Cut the excess cable. Connect wires
from the cable to the TB1 terminal in the junction box: black wire to B, white wire to W, and red wire to R.
Connect the cable shield wire to the Shield terminal between TB1 and TB2.
3. Route another 3-conductor cable through the tting into this junction box, and attach wires to the TB2
terminal: black wire to B, white wire to W, and red wire
CAUTION: ALL WIRING ROUTED BETWEEN JUNCTION BOXES AND SIGNAL PROCESSOR MUST
BE CONTINUOUS (NO SPLICES).
4. Repeat Steps 2 and 3 until all junction boxes for the vessel are wired together.
5. Route the cable from the last junction box through conduit to the signal processor. Refer to the signal
processor manual for wiring the junction box to the signal processor. One vessel takes up one channel in
the signal processor — the channel shows the average value from all the Load Stands supporting the
vessel.
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FIGURE 4: SIGNAL CABLE LAYOUT
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1.
2.
2
3.
4.
5.
6.
FIGURE 5: INTERCONNECT DIAGRAM
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VI. SET-UP
INSTALLING A SUN SHIELD
The sun shield reduces sun-induced stresses in the Load Stand sensors and provides additional protection for
the sensors.
1. With the junction box cover off, slightly loosen the screws attaching the junction box to the Load Stand.
2. Slightly loosen the horizontal screw(s) on the bottom ange of the Load Stand.
3. Wrap the sun shield around the Load Stand, slipping the cutout slots behind the loosened screws.
4. Tighten the junction box screws and the horizontal screw(s) on the bottom ange.
Example: You are using four S2-100K (100,000 lb) Load Stand IIs to monitor a vessel.
The vessel currently contains 50,000 lbs of material. The vessel can hold a maximum of 350,000 lbs. Following
the Manual calibration procedure:
1. Counts/mV = 699.05 (from signal processor)
2. Rated load for one Load Stand is 100,000 lbs.
3. S = 26.7 mV/V (from Table 4-1)
4. Excitation voltage = 12 V (from signal processor)
5. Current live load = 50,000 lbs
6. Calculate the calibration values:
Scale Factor Weight
= Rated Load x Number of supports
= 100,000 lbs x 4 legs = 400,000 lbs
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Scale Factor Counts
= S x Excitation Voltage (V) x Counts/mV
= 26.7 mV/V x 12 V x 699.05 Cnts/mV
= 223,975 Counts
Zero_Cal = current live load = 50,000 lbs
Note: Some installations have ‘dummy’ Load Stands under one or more legs. This does not affect the manual
calibration parameter calculation. Use the total number of supports, not the total number of Load Stands, in the
calculation.
ALTERNATE METHOD FOR CHECKING OUTPUT
If you do not have a Kistler-Morse Test Meter, use a Digital Multimeter (DMM) and the Load Stand II junction box
to monitor the voltage output of each Load Stand before and during installation. Set up the DMM as described
below.
1. Disconnect the white wires from the W terminals on TB1 and TB2 in the junction box, see Figure below.
2. Connect the DMM (+) probe to the W terminal on either TB1 or TB2 (See A).
3. Connect the DMM (-) probe to TP1 in the junction box (See B).
4. Set a voltage range on the DMM that will accommodate a measured range of ± 1 volt.
5. See Pre-Check Procedures, for details on checking the voltage output before installation. See Leveling
Vessel, Hardware Installation, for details on monitoring the voltage output to determine if the vessel
weight is evenly distributed among the Load Stands.
6. Once output is veried, reconnect the white wires on the W Terminals on TB1 and TB2 in the junction box.
LOAD STAND STANDARDIZATION
SENSOR A SENSOR B SENSOR C SENSOR D
12 VDC Excitation Voltage from
Signal Processor connected
across Black and Red Terminals
Cable from Previous Junction Box (if
B W R B W R B W R B W R
TB3
B W R SHLD B W R
TB1 TB2
applicable)
Cable to Next Junction Box or Signal Processor
TP1
TP2
TP3
(B) Connect DMM (-) probe
to TP1
(A) Connect DMM (+) probe
to either W Terminal (TB1
or TB2)
Using DMM and Junction Box to Monitor Voltage Output
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VII. TROUBLESHOOTING
SYMPTOMPOSSIBLE CAUSE SOLUTION
Small Amplitude
Changes or Erratic
Fluctuations in
Display Readings
Fluctuations can be caused
by small amplitude drift or
oscillation, with peak-to-peak
disturbance of 0.1% to 0.5% of
full scale, is normal.
Problem likely to be noticed
shortly after initial installation.
Reduce drift or oscillation by setting ‘count by’ and ‘averaging’ appropriately
on signal processor (refer to signal processor manual).
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Fluctuations can be caused by
moisture in the cable conduit,
junction boxes, or PCBs.
Problem likely to be noticed on
system that previously functioned
correctly.
Fluctuations can be caused by
jammed bolts or heat radiation/
conduction.
Problem likely to be noticed
shortly after initial installation
or on system that previously
functioned correctly in cool or
overcast weather.
Fluctuations can be caused by
damaged Load Stand sensor.
Problem likely to be noticed
shortly after initial installation
or on system that previously
functioned correctly.
Check conduit, junction boxes and PCBs for water contamination. Find
water entry source and correct problem. Dry with a hair drier. Remove/
replace corroded parts and materials.
CAUTION: If using sealant to eliminate water entry, use Sikaex 1A
polyurethane sealant or Dow Corning RTV 739 or RTV 738. Other sealants
may contain acetic acid, which is harmful to sensors and electronics.
Loosen nuts on top bolts and inspect top bolts.
• Top bolts free to move in holes: If vessel is heated, it may be radiating or
conducting heat through vessel legs and affecting Load Stand sensors.
• To reduce head radiation/conduction:
a. Insulate vessel.
b. Contact K-M to discuss adding a high temperature insulating pad.
• Top bolts jammed: Jammed top bolts indicate undersized bolt holes on
vessel mounting ange and/or vessel support movement beyond limits of
Load Stand clearance holes. Resulting side loads affect Load Stand
sensors.
• To reduce side loads:
a. Enlarge vessel mounting ange bolt holes to provide additional
clearance.
Using Digital Multimeter (DMM), check resistance for individual Load Stands:
1. Set meter resistance scale to accommodate measured range up to
20,000 ohms.
2. At the suspect Load Stand junction box, remove wiring at TB1 and TB2,
which connects to other Load Stands and signal processors.
3. Put one DMM lead on W and other lead on R terminal on TB1 of Load
Stand junction box. Record resistance, and verify it is 7,660 ± 200 ohms.
If reading is outside this range, one or more Load Stand sensors are
damaged and must be replaced— go to Step 7 to identify which sensor
is damaged.
4. Put one DMM lead on W and other lead on B terminal on TB1 of Load
Stand junction box. Record resistance, and verify it is 7,660 ± 200 ohms.
If reading is outside this range, one or more Load Stand sensors are
damaged and must be replaced — go to Step 7 to identify which sensor
is damaged.
5. Verify readings from Steps 3 and 4 are within 200 ohms of each other. If
not, one or more Load Stand sensors are damaged and must be
replaced — go to Step 7 to identify which sensor is damaged.
6. Repeat Steps 2 through 5 for each suspect Load Stand, until Load Stand
with damaged sensor is located.
7. Continued on next page.
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SYMPTOMPOSSIBLE CAUSE SOLUTION
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(Continued from
previous page)
Small Amplitude
Changes or Erratic
Fluctuations in
Display Readings
(Continued from previous page)
Fluctuations can be caused by
damaged Load Stand sensor.
Problem likely to be noticed
shortly after initial installation
or on system that previously
functioned correctly.
Fluctuations in readings can be
caused by short to ground.
Problem likely to be noticed
shortly after initial installation
or on system that previously
functioned correctly.
7. Identify damaged sensor at Load Stand identied in Step 3, 4, or 5:
a. Remove one sensors’s wires from junction box terminal TB3.
b. Put one DMM lead on sensor’s white wire and other lead on red wire.
Record resistance, and verify it is 7,660 ± 200 ohms. If resistance is
outside this range, sensor is damaged and must be replaced.
c. Put one DMM lead on sensor’s white wire and other lead on black
wire. Record resistance, and verify it is 7,660 ± 200 ohms. If resistance is outside this range, sensor is damaged and must be
replaced.
d. Verify readings from Steps B and C are within 200 ohms of each
other. If not, sensor is damaged and must be replaced.
e. Repeat Steps A through D for each sensor, until damaged sensor is
located and replaced.
Using a Digital Multimeter (DMM) or ohmmeter, check for shorts to ground
as follows:
1. Set meter resistance scale to accommodate maximum measured range.
2. Disconnect junction box wires of suspect vessel from signal processor.
3. With one lead to earth ground and other lead to white wire, check
resistance on disconnected wires:
• If reading is less than innite (i.e., there is resistance), a short is
indicated; proceed to Step 4 to identify location.
• If no short is indicated, investigate other explanations for problem.
4. Starting with junction box closest to signal processor in daisy chain,
disconnect wires connecting junction box to other junction boxes. With
one lead to earth ground and other lead to white terminal on TB3, check
resistance on wires leading from junction box:
• If the reading is less than innite (i.e., there is resistance), short is
indicated; proceed to Step 5 to identify location.
• If no short is indicated, proceed to next junction box in daisy chain,
disconnecting wires connecting it to other junction boxes and
checking resistance. Perform for each junction box down chain until
short is located; proceed to Step 5 to identify location.
Note: Sun shield or junction box mounting bolts are good locations for
connecting probe to ground.
5. Disconnect wires for one sensor from above-identied junction box. With
one lead to earth ground and other lead to white wire, check resistance
on disconnected sensor wires:
• If reading is less than innite (i.e.,there is resistance), short is
indicated. Replace shorted sensor.
• If no short is indicated, disconnect next sensor’s wires from junction
box and check resistances. Repeat for each sensor wired to junction
box until short is located. Replace shorted sensor.
Fluctuations in readings can be
caused by problems with signal
processor.
Problem likely to be noticed
shortly after initial installation
or on system that previously
functioned correctly.
Check signal processor excitation voltage and incoming AC voltage for
accuracy and stability (refer to signal processor manual).
22
97-1100-01 Rev. H
Page 27
SYMPTOMPOSSIBLE CAUSE SOLUTION
www.kistlermorse.com
Repeatable Drift
over 24-hour
Period
Sudden Change
in Weight Reading
or System
Requires Frequent
Recalibration
Periodic drift is most likely
caused by thermal expansion
due to sun’s radiation or vessel’s
response to its own heating
cycles.
Problem likely to be noticed
shortly after initial installation
or on system that previously
functioned correctly in cool or
overcast weather.
Sudden change in weight reading
can be caused by a broken Load
Stand, causing indicated weight
to shift up or down by large
amount, up to 100% of full-scale
live load.
Problem likely to be noticed on
system that previously functioned
correctly.
Loosen nuts on top bolts and inspect top bolts.
• Top bolts free to move in their holes— If vessel is heated, it may be
radiating or conducting heat through vessel legs and affecting Load
Stand sensors.
To reduce head radiation/conduction:
a. Insulate vessel.
b. Contact K-M to discuss adding a high temperature insulating pad.
• Top bolts jammed — Jammed top bolts indicate undersized bolt holes
on vessel mounting ange and/or vessel support movement beyond
limits of Load Stand clearance holes. Resulting side loads affect Load
Stand sensors.
To reduce side loads:
a. Enlarge vessel mounting ange bolt holes to provide additional
clearance.
b. Contact K-M to discuss adding a sliding pad if support movement
exceeds 0.125” (3mm).
If support movement and heat radiation/conduction have been eliminated as
source of error and periodic drift still indicates system is not meeting
specications (Appendix A), contact K-M.
NOTE: If keeping long-term records, take level readings at same time each
day to minimize error.
Check voltage outputs of individual Load Stands (refer to Chapter 2,
Pre-Check Procedures, the section titled Method 1: Measuring Output).
Voltage should be between -750 mV and +750 mV on installed Load Stands.
If not, check Load Stand resistance as described above in Problem 1.
Sudden change in weight reading
can be caused by problems with
signal processor.
Problem likely to be noticed
shortly after initial installation
or on system that previously
functioned correctly.
Check signal processor excitation voltage and incoming AC voltage for
accuracy and stability (refer to signal processor manual).