Rice Lake Survivor ATV Portable Truck Scale

2.1 Deck Module Assembly:

Note: The bridge module is placed last and should be set aside during unloading.

1. Place the first self-contained module on a flat surface, positioning the J-box towards the indicator. (See Figure 2-1: Module Placement diagram)
2. Install spacer tubes to the first module using supplied hardware. (See Figure 2-2: Spacer Tube Installation diagram)
3. Position the second self-contained module at the other end of the spacer tube, ensuring its J-box also faces the indicator.
4. Remove load cell cover plates (using a 5/16 in Allen wrench) and place the bridge module into the receptacles on the self-contained modules. Note: Check receptacles for debris. Ensure pins seat squarely; slightly raise and reset the module if needed for proper alignment. (See Figure 2-3: Pin and Receptacle Interface image and Figure 2-4: Two Self-Contained Module Connection diagram)

2.2 Setup:

1. Back off weighbridge shipping bolts (four per module) until they are no longer inserted. (See Figure 2-5: Weighbridge Shipping Bolts image)
2. Remove the bolt connecting the stand to the bulkhead base. Re-install this bolt in the bulkhead base after raising the stand in Step 4. (See Figure 2-6: Bolt Connecting Stand to Bulkhead image)
3. Jack up each corner of the scale to remove weight from the stand in the load cell pocket.
4. Remove the hitch pin holding the stand up. (See Figure 2-7: Hitch Pin and Chain image)
5. Lift the stand using the chain inside the load cell pocket. (See Figure 2-7: Hitch Pin and Chain image)
6. Re-install the bolt and hitch pin; the stand will remain in the retracted position.
7. Slowly lower the weighbridge onto the load cell link and remove the jack. Repeat for all load cell pockets.
8. Connect the expansion cable between J-boxes on the self-contained modules.
9. Wire the home run cable and indicator.
10. Apply anti-seize compound to bolt threads and install load cell cover plates.
11. Install bolt-on wings. (See Figure 2-8: Bolt-on Wing diagram)
12. Back fill material against bulkheads to create a ramp as needed.
13. Calibrate the scale (refer to Trimming and Calibration section).

2.3 Scale Relocation:

Follow these steps to relocate the ATV portable truck scale:

1. Remove load cell cover plates. (See Figure 2-9: Load Cell Cover Plate Removed image)
2. Remove the hitch pin holding the stand in the retracted position. (See Figure 2-9: Load Cell Cover Plate Removed image)
3. Jack up each corner of the module until the hitch pin can be re-installed in the shipping position.
4. Install the bolt connecting the stand to the bulkhead base. (See Figure 2-6 on page 10)
5. Install shipping bolts on the ends of the modules. (See Figure 2-5 on page 10)
6. Remove the home run cable and expansion cable.
7. Remove spacer tubes.
8. Remove backfill material.
9. Relocate modules, starting with the bridge module.

3.1 Indicator to Peripherals:

Diagram Description (Figure 3-1): Shows a conduit run in a trench.

Conduit runs can be buried or secured above ground. Use separate conduit runs for AC power and DC data lines to prevent interference. If AC and DC cables must share a trench, keep them separated as much as possible.

3.2 J-Box Connections:

Each J-box contains a JB8SPT summing board with DC transient protection. Add a desiccant (RLWS Industrial Corrosion Inhibitor, PN 16037) to the J-box before closing. Each self-contained module has one J-box in its pocket. A summing card within the J-box makes all cable terminal connections; terminal pins are clearly marked.

Diagram Description (Figure 3-2): Detailed diagrams illustrate J-Box wiring and conduit connections for J-Box 1 and J-Box 2.

3.3 Single-Point Ground Conductor:

A bare 10-gauge solid wire runs from the scale frame to the main AC power earth ground. Proper grounding is essential for DC transient protection.

3.4 Electrical Ground Connections:

ℹ️ IMPORTANT: Improper grounding can lead to corrupted data and lightning damage. Always strive for a single-point grounding system.

Avoid driving separate ground rods at the scale location, as this creates potential differences that can corrupt data or invite lightning damage. The scale should use the same grounding system as the incoming AC power. The 120 VAC power source connects to an existing earth-grounded rod system at the scale house. This typically involves a double ground rod system (two 5/8 in x 8 ft copper rods driven 8 ft deep) at the service entrance.

The local utility company can test grounding resistance. If inadequate, improvements must be authorized and made by the scale owner. Do not connect the scale until the grounding system is adequate.

Ensure each load cell grounding strap is securely connected to the load cell mount plates. Inter-module straps ensure the entire scale is connected to the single-point ground, with metal-to-metal contact. Apply anti-oxidant grease to ground connections to prevent corrosion.

A separate grounding conductor must run uninterrupted from the main service panel ground to the scale. Use an unsheathed #10 copper wire or larger. Run this wire in a separate trench and attach it to the ground lug in the J-box pocket. This grounds the scale frame to the same single-point ground as the AC power for the indicator. Grounding the J-box is crucial for its DC transient protection.

3.5 Installing Transient Protection:

A two-year lightning protection package is standard, protecting AC and DC system components. It includes:

• DC transient protection with J-box board(s) (handles up to eight load cells; more require additional J-boxes).
• Self-contained DC transient protection unit in the home run cable at the indicator.
• A 115 VAC uninterruptable power supply/surge protector in the AC line before the indicator.
• #10 bare ground conductor cable from scale frame to DC transient board at indicator, then to AC power ground lug.

Diagram Description (Figure 3-3): Illustrates the grounding and transient protection setup on an ATV Scale, showing the ground lug in the J-box pocket and the ground wire connection.

Note: Serial communications may also require transient protection. A TP-232 DC Transient Protection is suitable for serial lines. Printers, remote displays, and other serial devices should also have AC transient protection.

Diagram Description (Figure 3-4): A schematic diagram detailing the single-point grounding system, showing connections from the power company ground rod, fuse panel, indicator, printer, and scale components.

4.1 Overview and Equipment Required:

4.1.1 Load Cell Trimming:

Individual load cell signal trimming equalizes output from each cell. This is done first along each side of the scale, then by trimming paired cells across the scale. Each side and section should be trimmed at least twice.

Diagram Description (Figure 4-1): Depicts the load cell trimming sequence: 1st - Trim Side 1 Cells (1, 2, 3, 4); 2nd - Trim Side 2 Cells (5, 6, 7, 8); 3rd - Trim Sections (1,8; 2,7; 3,6; 4,5).

4.1.2 Equipment Required:

Trimming can be performed using a weight cart. Final verification requires test weights placed on the deck.

4.2 Trimming Individual Cells:

Connect all load cells to the J-box summing board and the interface cable to the indicator. Power on the indicator. Turn all load cell potentiometers (individual and section) fully clockwise. Refer to the J-box manual for jumper and dip switch settings before proceeding.

4.2.1 Side 1:

Adjust individual load cells on one side (Side 1) for equal signal output when equal weight is applied. Use a loaded weight cart.

1. Park the cart near Side 1, centered over the end load cell mount (No. 1). Record the indicator reading (raw counts). (See Figure 4-2: Trimming Load Cell Number One diagram)
2. Move the cart over mount No. 2, record reading. Repeat for mount No. 3, then mount No. 4. (See Figure 4-3: Trimming Load Cell Numbers 2, 3, and 4 diagram)
3. Identify the lowest reading as the reference cell. Adjust the other three cells' potentiometers to match this reference. Signals can only be decreased.
4. Aim for the least trim. If readings differ by more than 5%, check for mechanical issues like binding or misalignment. Do not compensate for large differences with pots.
5. Park the cart over a high-reading cell on Side 1. Adjust its potentiometer until the reading matches the reference. Repeat for the other two high-reading cells.
6. Repeat steps 1-5 until all four cells on Side 1 read within 0.1% of each other.
7. Repeat steps 1-6 for load cells 5-8 on Side 2.

4.3 Trimming Paired Sections:

Trim pairs of load cells on opposite sides for equal sectional output.

1. Park the weight cart in the middle of the scale, centered over the line connecting an end pair of cells (1 and 8). Record the reading. (See Figure 4-4: Trimming Paired Section 1:8 diagram)
2. Move the cart over the next paired section (2 and 7). Record the reading. Repeat for sections (3, 6) and (4, 5). (See Figure 4-5: Trimming Paired Sections 2:7, 3:6, and 4:5 diagram)
3. Choose the lowest reading as the reference section. Use section potentiometers to adjust the other three sections to match the reference reading. Recheck readings.
4. Perform a final corner check: place a 1000 lb weight on each corner and record readings. They should be within 0.1% of each other.

4.4 Calibrating with Test Weights:

Calibration requires a qualified scale technician with a test weight truck and indicator setup expertise.

Diagram Description (Figure 4-6): Shows test weights placed on the scale for calibration.

4.4.1 Equipment Required:

Truck scales are typically calibrated using 25% of capacity. Certified Class F test weights (at least 12.5% of capacity) are required for legal-for-trade scales, plus an additional 12.5% substitution weight (e.g., test-weight truck, sand bags). Industrial scales not used for legal-for-trade transactions require 25% of capacity weight for calibration.

Refer to NIST Handbook 44 for detailed calibration requirements.

5.1 Replacement Procedure:

1. Position a jack under a weighbridge main frame member near the load cell mount. Raise the jack approximately 1/2 inch and place setting block(s) under the scale deck. ? CAUTION: Always use setting blocks when jacking scale modules.
2. Disconnect load cell terminal connections in the junction box.
3. Disconnect the flex conduit from the rigid conduit at the frame. Note: Attach a pull cord to the load cell cable at the J-box before pulling.
4. Pull the load cell cable out of the conduit.
5. Remove the two load cell bolts and lift out the load cell and link assembly. (See Figure 5-1: Load Cell Replacement diagram)
6. Remove the 90-degree conduit connector and flex cable. Install new connector and flex conduit on the new load cell.
7. Install the link over the new load cell. Reinstall the load cell and link assembly onto the baseplate. Install load cell mount bolts and torque to 50-75 ft-lb.
8. Pull the load cell cable through the conduit using the pull cord. Create a loop in the flex conduit between the load cell and rigid conduit. Reconnect the flex conduit.
9. Remove setting blocks and lower the scale module so it rests on the link. Verify the link is centered and plumb.
10. Connect wiring to terminals in the junction box.

Note: RLWS offers shims (1/4 in, 1/8 in, 1/16 in) for leveling. Do not exceed 3/4 inch of combined shims.

5.2 End Clean-outs:

End clean-outs are standard. Remove bolts and cover plate for access. Apply anti-seize compound to bolt threads before re-installing the cover plate.

Diagram Description (Figure 5-2): Shows end clean-outs with bolts and cover plate removed.