Master 311, 311M, Master 711 Belt Scale Weigh Frames
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Specifications
- Product Name: MASTER 311, 311M and 711 Belt Scale Weigh
Frames - Date: June 23, 2025
- Model Number: PN 170735 Rev C
Product Information
The MASTER 311, 311M, and 711 Belt Scale Weigh Frames are
designed to measure continuous mass flow on a belt conveyor. The
system includes a weigh frame with load cells, a speed sensor, and
integrator electronics. These belt scales are suitable for various
applications and conveyor types.
Installation
To install the belt scale:
- Refer to the Installation Manual for detailed
instructions. - Ensure proper mechanical adjustments are made as per section
2.4.1.
Mechanical Adjustments
Mechanical adjustments are crucial for accurate readings. Follow
the guidelines in section 2.4.1 of the manual to calibrate the
system correctly.
Maintenance
Regular maintenance is essential for optimal performance. Refer
to section 3.1 for detailed maintenance instructions.
Periodical Maintenance
Perform periodical maintenance tasks outlined in section 3.1.1
to keep the belt scale functioning properly.
FAQ
Q: Where can I find manuals for the product?
A: Manuals can be accessed at www.ricelake.com/manuals.
Q: How can I get warranty information?
A: Warranty details are available at
www.ricelake.com/warranties.
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MASTERTM 311, 311M and 711
Belt Scale Weigh Frames
Installation Manual
June 23, 2025
PN 170735 Rev C
© Rice Lake Weighing Systems. All rights reserved.
Rice Lake Weighing Systems® is a registered trademark of Rice Lake Weighing Systems.
All other brand or product names within this publication are trademarks or registered trademarks of their respective companies.
All information contained within this publication is, to the best of our knowledge, complete and accurate at the time of publication. Rice Lake Weighing Systems reserves the right to make changes to the technology, features, specifications and design of the equipment without notice.
The most current version of this publication, software, firmware and all other product updates can be found on our website:
www.ricelake.com
Revision History
This section tracks and describes manual revisions for awareness of major updates.
Revision
A B C
Date
Description
February 14, 2018 Initial release July 30, 2021 June 23, 2025 Updated Selection Criteria and format; added disposal information
Table i. Revision Letter History
Revision History
Technical training seminars are available through Rice Lake Weighing Systems. Course descriptions and dates can be viewed at www.ricelake.com/training or obtained by calling 715-234-9171 and asking for the training department.
© Rice Lake Weighing Systems All Rights Reserved
3
MASTER 311, 311M and 711
Contents
1.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.3 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.4 Selection Criteria. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.5 Calibration and Test Weight Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.0 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1 Mechanical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.1.1 311/311M Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.1.2 Adjusting 311M Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.1.3 711 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.2 Splice Box Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.3 Electrical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.4 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.4.1 Mechanical Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.0 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.1 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3.1.1 Periodical Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.2 Dimensional Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.2.1 311 Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.2.2 711 Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.3 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3.4 Total Load Cell Build . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3.5 List Parameters for Belt Scale. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Rice Lake continually offers web-based video training on a growing selection of product-related topics at no cost. Visit www.ricelake.com/webinars
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Introduction
1.0 Introduction
Belt scales measure a continuous mass flow, which is transported over a belt conveyor. A complete belt scale is composed of a weigh frame, which contains one or more load cells, a speed sensor/pickup and the integrator electronics. Not every application is suited for a belt scale; this has to be analyzed by a Rice Lake Weighing Systems specialist. To achieve the optimum result, the MasterTM belt scale series has been developed for a number of applications and for every type of conveyor.
i Manuals are available from Rice Lake Weighing Systems at www.ricelake.com/manuals Warranty information is available at www.ricelake.com/warranties
1.1 Safety
Safety Definitions:
DANGER: Indicates an imminently hazardous situation that, if not avoided, will result in death or serious injury. Includes hazards that are exposed when guards are removed. WARNING: Indicates a potentially hazardous situation that, if not avoided, could result in serious injury or death. Includes hazards that are exposed when guards are removed.
CAUTION: Indicates a potentially hazardous situation that, if not avoided, could result in minor or moderate injury.
IMPORTANT: Indicates information about procedures that, if not observed, could result in damage to equipment or corruption to and loss of data.
General Safety
Do not operate or work on this equipment unless this manual has been read and all instructions are understood. Failure to follow the instructions or heed the warnings could result in injury or death. Contact any Rice Lake Weighing Systems dealer for replacement manuals.
WARNING Failure to heed could result in serious injury or death. Some procedures described in this manual require work inside the enclosure. These procedures are to be performed by qualified service personnel only. Take all necessary safety precautions when installing the scale carriage including wearing safety shoes, protective eye wear and using the proper tools. Keep hands, feet and loose clothing away from moving parts. Do not approach a running conveyor from underneath. Do not bend over a running conveyor. Do not allow minors (children) or inexperienced persons to operate this unit. Do not operate without all shields and guards in place. Do not jump on the scale. Do not use for purposes other then weight taking. Do not place fingers into slots or possible pinch points. Do not use any load bearing component that is worn beyond 5 percent of the original dimension. Do not use this product if any of the components are cracked. Do not exceed the rated load limit of the unit. Do not make alterations or modifications to the unit. Do not remove or obscure warning labels.
© Rice Lake Weighing Systems All Rights Reserved
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MASTER 311, 311M and 711
1.2 Disposal
Product Disposal The product must be brought to appropriate separate waste collection centers at the end of its life cycle. Proper separate collection to recycle the product helps prevent possible negative effects on the environment and to health, and promotes the recycling of the materials. Users who dispose of the product illegally shall face administrative sanctions as provided by law.
1.3 Overview
The weigh frame model Master 311/711 Series is designed for medium and heavier applications in the process industry, where accuracy and/or legal approval is required. The dimensions are extracted from the construction of the existing, or to-be built, belt conveyor.
Theory of Operation The material is carried by the belt and underlying rollers or idler stations. One or more of these idlers are mounted on the weigh frame and are used to weigh the material going across the belt. The material carried on the belt is weighed and the belt speed is measured. Both values (belt load and belt speed) are calculated in an integration function. The integrator totals and calculates the mass flow. These values are displayed and transmitted through outputs or other forms of communication to a control system or network. For the operation, refer to the manual of the electronics installed.
1.4 Selection Criteria
Load cell capacity is calculated based on the maximum belt load plus the dead load of the weigh frame and the weight of the rollers. Net load = (conveyor capacity / belt speed) x idler spacing Gross load = net load + (idler weight + belt weight + mounting hardware)
Example (Imperial): Net load = (20,000 lb per minute / 400 ft per minute) x 4 ft spacing Net load = (50 lb per ft) x 4 ft spacing Net load = 200 lb Gross load = 200 lb + (175 lb idler + 48 lb belt + 24 lb hardware) Gross load = 447 lb
NOTE: In this example, a minimum of a 500 lb (227 kg) load cell should be used.
Example (Metric): Net load = (24,000 kg per minute / 120 meters per minute) x 1 meter spacing Net load = (200 kg per meter) x 1 meter spacing Net load = 200 kg Gross load = 112 kg + (90 kg idler + 15 kg belt + 7 kg hardware) Gross load = 312 kg
NOTE: A minimum of 500 kg load cells should be used in this example.
1.5 Calibration and Test Weight Device
Mounting points can be provided to apply static test weights. Test weights are used to test repeatability and the state of the belt scale after initial calibration. To determine absolute accuracy, it is necessary to do a test with material. For this procedure, refer to the manual of the electronics installed.
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Installation
2.0 Installation
Installation procedures generally should be a combination of the end user’s best engineering practices in compliance with local codes and the manufacturer’s recommendations. To achieve maximum performance, the following precautions should be observed.
IMPORTANT: Failure to heed the following statements could result in severe injury or death.
* Take all necessary safety precautions when installing the scale carriage including wearing safety shoes, protective eye wear and using the proper tools.
* Always turn off the power supply before any connection is made or removed. * Before welding, the power supply must be off and the connectors removed.
IMPORTANT: Failure to heed the following statements could result equipment damage and void the warranty.
* The load cell is very sensitive to damage by welding. The welding ground clamp must be attached to the same side of the weigh frame where welding. When in doubt, remove the load cell(s).
* Follow the recommendations given when the application was checked. * Belt conveyor must be installed in a stable and rigid area, free from vibrations. * The construction of the belt frame must be stiff enough to prevent torsion or bending at the maximum load (including the weigh frame). * The weigh frame must be mounted free of mechanical tensions. * No vibrations in the conveyor should be allowed to carry over to the weigh frame. If needed, these must be filtered. * The belt must be of good quality and a single splice. A vulcanized splice will provide the best accuracy. The weight per foot (meter) should be
consistent over the whole length. * The belt must not track out of the center and no steering idler must be placed near the weighing area. * The belt support must not be supported with two-part (v-shape) idler stations. * At least three idler stations before and three idler stations after the weigh frame (the weighing section) have to be adjustable in height. For
short belt conveyors this can be reduced to one roller before and one roller after the weigh frame. * String alignment should be used on all idlers in the scale system. If following the rule of three before and three after, seven idlers (including
the weigh idler) should be checked during the alignment process. * Rollers should not have a concentricity exceeding +/- 0.012 in (0.3 mm). * The speed sensor should be mounted on a non-driven roller or drum. * The inclination angle of the belt conveyor must not exceed 12%. * Proper covers may be required to prevent air flow from interfering with the belt scale. * Side guards and belt skirting should not be in contact with the weighing area of the belt scale.
© Rice Lake Weighing Systems All Rights Reserved
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MASTER 311, 311M and 711
2.1 Mechanical Installation
The mechanical installation of a belt scale consists of mounting the belt scale, the speed pickup and the junction box. Three types of scale installation are included in this manual:
311 a weigh frame that is made to order, lengths will vary. 311M a modular weigh frame, the width can be adjusted in the field for smaller conveyors. 711 a pivot weigh frame that is made to order, lengths will vary. 2.1.1 311/311M Installation The 311/311M width can be adjusted slightly to fit across the stringers of the belt conveyor.
NOTE: The length of the 311M can be shortened, see Section 2.1.2 on page 10.
1. Determine the location for the belt scale. This location should be at least five idlers after the load point of the conveyor and at least five idlers before the head pulley.
2. Remove the belt from the selected area. 3. Remove the existing idler where scale is to be located.
Remove mounting brackets
Figure 2-1. Remove Existing Idler 4. Remove any mounting brackets that may be attached to the idler. 5. Adjust the weigh frame to fit between the conveyor frame stringers. To adjust the end brackets, loosen the bolts
allowing the bracket to slide back and forth in the bracket slots. Ensure the length of the slots are sitting on the conveyor stringers.
Figure 2-2. Adjust Belt Scale Width 6. Align the weigh frame mounting bracket slots with the holes used for anchoring the idler.
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7. Use the existing hardware from the idler to secure the weigh frame to the conveyor stringers.
Idler Clamp
Installation
Figure 2-3. Installed 311/311M Weigh Frame
8. Remove the idler clamps from the weigh frame assembly. 9. Place the idler on top of the weigh frame. 10. Place the idler clamps on the idler bottom stringer and secure with bolts, washers and nuts.
Idler Clamp
Idler Clamp
Figure 2-4. Install Idler On Weigh Frame 11. Run strings on the conveyor (three before the scale and three past the scale) and shim the idlers to the same plane.
Figure 2-5. Run Strings To Same Plane NOTE: Shims are not included with scale. They are available separately.
© Rice Lake Weighing Systems All Rights Reserved
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MASTER 311, 311M and 711
2.1.2 Adjusting 311M Length 1. Measure the distance between the stringers at the location selected for the belt scale.
Figure 2-6. Measure Length Between Stringers 2. Remove angle bracket, flat plate and idler clamp from both ends of weigh frame. 3. Using the measurement from step one determine how much needs to be cut off from the weigh frame. Divide this
number by two; this is the amount to be cut off from each end of the weigh frame. 4. Measure carefully from each end of the weigh frame to cut off the exact same amount on each side.
IMPORTANT: Carefully measure each end of the weigh frame. The exact same amount must be removed from each side to ensure accurate weighing.
Ensure cuts are equal on both ends.
Figure 2-7. Resize Weigh Frame 311M Only 5. Reinstall angle bracket, flat plate and idler clamp to both ends of weigh frame. 6. Proceed with installation. See Section 2.1.1.
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Installation
2.1.3 1.
2.
711 Installation Determine the location for the belt scale. This location should be at least five idlers after the load point of the conveyor and at least five idlers before the head pulley.
Remove the existing idler where scale is to be located.
Remove mounting brackets
Figure 2-8. Remove Existing Idler 3. Remove any mounting brackets that may be attached to the idler. 4. Align the weigh frame mounting bracket slots with the holes used for anchoring the idler. 5. Use the existing hardware from the idler to secure the weigh frame to the conveyor stringers.
Idler Clamp
Figure 2-9. Installed 711 Weigh Frame 6. Remove the idler clamps from the weigh frame assembly. 7. Place the idler on top of the weigh frame.
© Rice Lake Weighing Systems All Rights Reserved
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MASTER 311, 311M and 711 8. Place the idler clamps on the idler bottom stringer and secure with bolts, washers and nuts.
Idler Clamp
Idler Clamp
Figure 2-10. Install Idler on 711 Weigh Frame
9. Run strings on the conveyor (three before the scale and three past the scale) and shim the idlers to the same plane. See Figure 2-5 on page 9.
Transport Lockout The 711 is equipped with a transport lockout, to engage when conveyor is being moved.
Transport Belt Scale
Figure 2-11. Transport Lockout
1. Loosen jam nut. 2. Turn transport bolts in to remove load from load cell. 3. Tighten jam nut so bolt cannot change position.
To Use Belt Scale 1. Loosen jam nut. 2. Turn transport bolts out to allow load onto load cell. 3. Tighten jam nut so bolt cannot change position.
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2.2 Splice Box Installation
1. Mount the splice box in an appropriate location.
Installation
Splice Box
Splice Box
Figure 2-12. Mount Splice Box
2. Wire load cells according to the load cell data sheets. 3. Terminate homerun cable at the splice box and integrator. 4. Calibrate the scale using the calibration procedure for the applicable integrator.
2.3 Electrical Installation
The wiring and connections between the weigh frame, speed pickup and the electronics are shown in the applicable scheme. See Section 3.3 on page 16. The load cell is provided with a fixed cable; do not alter the length. If necessary, use an additional junction box with screw terminals to extend the cable length.
Cable Types Load cell – If the length is more than 197”(60 m), use shielded 6 wire cable 20 AWG gauge (0.5 mm²). Speed pickup – Use shielded 3 wire cable 20 AWG gauge (0.5 mm²). Cable shielding – Cable shielding must be connected to one side only. If connected to the instrument side, then it is preferred to use the same ground as the power supply.
2.4 Commissioning
Commissioning should be performed by service engineers who are trained and experienced with the subject.
2.4.1 Mechanical Adjustments Mechanical adjustments must be made to ensure the scale is free of any tension. If necessary, the load cell can be adjusted.
© Rice Lake Weighing Systems All Rights Reserved
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MASTER 311, 311M and 711
3.0 Maintenance
Regular maintenance is essential to prevent errors or unnecessary down time. The supplier does not accept any responsibility for the consequences of not performing the maintenance recommended in this section.
3.1 Maintenance
IMPORTANT: It is important to ensure the safety of personnel during maintenance work and that no accidents will happen. Before any work on electrical systems is started, be sure to remove the main power supply. The conveyor must be shut off before any work on the conveyor is started. Any goods on the conveyor must be removed first. No unauthorized persons are allowed in the conveyor’s working area.
3.1.1 Periodical Maintenance To keep the belt scale in optimal condition, it is important to perform periodical maintenance.
· Ensure there is not a build up of debris on the belt. · Inspect the weigh frame for damaged areas and repair as necessary. · Regularly perform an Auto Zero and a weight check with certified test weights to determine if the belt scale weighs
correctly. For this procedure, refer to the manual of the electronics installed.
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3.2 Dimensional Drawings
3.2.1 311 Dimensions The 311 lengths will vary, they are made to order.
9.45 in (240.03 mm)
59.56 in (1512.82 mm)
4.84 in (122.93 mm)
21.50 in (546.10 mm)
Figure 3-1. 311/311M Weigh Frame
NOTE: The length of the 311M can be shortened, see Section 2.1.2 on page 10.
3.2.2 711 Dimensions The 711 lengths will vary, they are made to order.
48.40 in (1229.36 mm) Adjustable to order
39.75 in (1009.65 mm) Adjustable to order
G
4.00 in (101.60 mm)
30.00 in (762.00 mm) Adjustable to order
3.40 in (86.36 mm)
Section G-G Figure 3-2. 711 Weigh Frame
Maintenance
G
© Rice Lake Weighing Systems All Rights Reserved
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MASTER 311, 311M and 711
3.3 Specifications
Standard
Weigh Frame Material Weight Load Cell
Powder coated mild steel or stainless steel SS304 / 316 Approximately 104 lb (47 kg), not including the idler 1 potted single point load cell Capacity 50 to 250 kg (each) Power supply 5-15 VDC (stabilized from electronics) Signal nominal 2 mV/V at 100% load
3.4 Total Load Cell Build
The Master 311/711 Series has a single load cell. Table 3-1 outlines the total load cell build, this value is used for the theoretical calibration.
Load Cell Capacity Imperial
Metric
50 kg 100 kg 250 kg
110 lb 220 lb 550 lb
50 kg 100 kg 250 kg
Table 3-1. Total Load Cell Build Conversion
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3.5 List Parameters for Belt Scale
Complete the information below. Remove this page and store in a secure location.
CUSTOMER ORDER NUMBER INSTALLATION REFERENCE TYPE WEIGH FRAME TYPE SPEED PICKUP TYPE ELECTRONICS
DATE FILLED IN BY
Parameter
Nominal capacity (flow) Maximum capacity (flow) Minimum capacity (flow) Ratio weigh frame Number of load cells Load cell capacity (per load cell) Load cell sensitivity Idler spacing Belt angle of incline Belt speed Speed pickup: Pulses per revolution Non-driven drum Total belt length
Unit lb/hr (kg/hr) lb/hr (kg/hr) lb/hr (kg/hr)
lb (kg) mV/V in (mm)
° ft/s (m/s)
in (mm) ft (m)
Entered
Maintenance Change
© Rice Lake Weighing Systems All Rights Reserved
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MASTER 311, 311M and 711
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© Rice Lake Weighing Systems Content subject to change without notice. 230 W. Coleman St. · Rice Lake, WI 54868 · USA USA: 800-472-6703 · International: +1-715-234-9171
June 23, 2025
www.ricelake.com
PN 170735 Rev C
Documents / Resources
 |
RICE LAKE WEIGHING SYSTEMS Master 311, 311M, Master 711 Belt Scale Weigh Frames [pdf] Instruction Manual Master 711 Belt Scale Weigh Frames, Master 711, Belt Scale Weigh Frames, Scale Weigh Frames, Weigh Frames, Frames |