Table of Contents
Preventive maintenance of industrial platform weighing scales is crucial for several reasons. Firstly, it ensures the accuracy and reliability of weight measurements, which is essential for quality control and compliance with regulatory standards. Regular maintenance helps detect and address issues early, minimizing downtime and costly repairs. It extends the lifespan of the weighing scale, optimizing the return on investment. Preventive maintenance also enhances workplace safety by reducing the risk of equipment failures and accidents.
Safety
- Conduct a risk assessment to identify potential safety hazards and implement appropriate control measures before initiating maintenance activities.
- Locate the platform weigh scale that you want to do PM. Make sure the weigh scale is the right one and write down any important information on the tag, such as the manufacturer, model number, range, etc.
- Disconnect the power supply to the weigh scale. Ensure that any nearby junction boxes or marshalling panels close to the control room have their power sources switched off.(For instance, shut off the circuit breaker or unplug the wires).
- Ensure that the weighing scale is disconnected from the power source and that all electrical connections are safely isolated to prevent electric shock hazards
- Before calibrating the platform weigh scale, the PM area should be blocked off with barricades, and the process area should have the appropriate signboards placed to redirect traffic there.
- Implement proper lockout/tagout procedures to secure the weighing scale and prevent accidental startup or operation during maintenance activities.
- If necessary, use proper lifting techniques or equipment when handling heavy components to avoid strain or injuries to yourself or others.
- Wear appropriate PPE such as gloves, safety glasses, and protective clothing to protect against potential hazards or injuries.
- Ensure that the work area is clean, organized, and free from obstacles to minimize the risk of slips, trips, or falls during maintenance procedures.
- Inspect and ensure the proper functioning of tools and equipment to be used during maintenance, reducing the risk of accidents or malfunctions
Inspection of weighing indication and control unit
- Keep the weight indicator clean and free from dirt, dust, or debris. Use a soft, lint-free cloth or compressed air to clean the external surfaces.
- Regularly inspect the power, load cell and communications cables and connectors for any signs of damage or wear. Check for loose connections and ensure proper cable routing.
- Periodically verify the calibration of the weight indicator to ensure accurate readings. Follow the manufacturer’s guidelines or consult a calibration procedure for platform weighing scale for calibration checks.
- Verify the stability and integrity of the power supply for the weight indicator. Check for any fluctuations or irregularities that may affect its performance.
- Verify the grounding connection within the weighing control unit to ensure electrical safety. Make sure the grounding wire is securely connected and in good condition.
- Verify the condition of the cable gland are tight in the weighing control unit.
- Check to see that the excitation voltage, sensing voltage, and load cell output mV signal are all stable and free from drops or variations.
- Perform routine tests of the weight indicator system, including input and output signals, communication interfaces, and any connected peripheral devices.
- Protect the weight indicator from extreme temperatures, moisture, and excessive vibrations. Ensure proper ventilation and maintain suitable operating conditions.
- Check the display for any anomalies, such as faded segments or malfunctioning pixels. Test the keypad buttons to ensure proper functionality.
- Stay up to date with the latest software and firmware releases provided by the manufacturer. Check for available updates on a regular basis and install them when instructed to do so.
- Examine the condition of the operating key on the weighing control device; if it is defective, it must be replaced.
- Make sure that the parameter is correct by consulting the instrument data sheet or the commissioning report.
- Check that the weighing control unit’s communication function is working properly with the control system.
- Check the display of the weighing unit for any error codes, and then, with the help of the manufacturer’s instructions, correct the issue that is associated with the error code.
Inspection of average card junction box
- Conduct a visual examination of the junction box, looking for any signs of physical damage, such as cracks, corrosion, or loose connections.
- Check the cables connected to the junction box for any signs of wear, fraying, or damage. Ensure proper routing and cable management to prevent strain or interference.
- Verify the tightness of all electrical connections(load cell wires , shields and main cable) within the junction box. Ensure that wires are securely connected and that there are no loose or exposed connections.
- Inspect the sealing or gasket of the junction box to ensure it is intact and properly sealing the box. This helps protect the internal components from moisture or dust ingress.
- Clean the junction box regularly to prevent the buildup of dust, debris, or other contaminants that could interfere with the operation of the electrical connections or components.
- Verify that the terminals of the average card junction box have stable excitation voltage, sensing voltage, and all load cell output mV signal without any drops or changes.
- By measuring each mV load cell output and comparing it to a single output from the average circuit board, you can confirm the average functioning of the board.
- Check the labeling and drawing inside the junction box, ensuring that it is clear and up to date. This helps in identifying and troubleshooting any issues during maintenance or repairs.
- Inspect the condition of the cable gland are good and tight in the load cell junction box.
Inspection of Weighing platform/frame
- Conduct a thorough visual examination of the weighing platform, looking for any signs of physical damage, such as cracks, dents, or bent sections. Inspect the welding points and structural integrity.
- Keep the weighing platform clean from dirt, debris, and foreign materials. Regularly remove any build-up that could affect accuracy or cause damage to the platform.
- Verify that the weighing platform is properly leveled. Use a spirit level to check for any unevenness and adjust the leveling feet if necessary.
- Inspect the load cells, which are responsible for weight measurement, for any signs of damage, corrosion, or loose connections. Ensure the load cells are properly mounted and aligned.
- Periodically verify the calibration of the weighing platform using certified weights. Follow the manufacturer’s guidelines or consult calibration procedure to ensure accurate readings.
- If the weighing scale has moving parts, follow the manufacturer’s instructions for lubrication. Use recommended lubricants sparingly and avoid applying them directly to load cells or weighing surfaces.
- Examine the mounting of the platform in the weighing scale to ensure that it is secure.
- Inspect the cables connecting the weighing platform to the indicator or control system. Look for any signs of wear, fraying, or loose connections. Ensure proper cable routing and management.
- Ensure the weighing surface is intact, free from scratches, and capable of providing a stable and flat area for weighing objects.
- Always make sure that there is no debris in the space between the weighing platform and the pit frame.
Inspection of load cells under the platform
- Keep the load cells clean from dirt, dust, and debris. Use a soft cloth or brush to remove any particles that may affect their performance.
- Conduct visual inspections of the load cells for signs of physical damage, such as cracks, corrosion, or deformation. Address any issues promptly.
- Inspect the cables connected to the load cells for any signs of wear, fraying, or damage. Ensure proper cable routing and management to prevent strain or interference.
- Verify the tightness of all electrical connections to the load cells, ensuring that wires are securely connected and there are no loose or exposed connections.
- Check the mounting of the load cells to ensure they are securely attached and mechanically aligned properly. Inspect the mounting hardware for any signs of damage or loosening.
- To ensure that the weighing platform moves the least possible amount, check and adjust the buffer stop.
- Inspect the seals or gaskets around the load cells to ensure they are intact and properly sealing the load cells from moisture or debris ingress.
- Assess the environment in which the load cells are installed. Ensure they are protected from extreme temperatures, moisture, corrosive substances, and excessive vibrations.
- Verify that the load cells’ mounting bolts and other mechanical protection devices, such as lock nuts, stoppers, and other accessories, are in good working order.
- After disconnecting the load cell cable from the circuit, measure and record the input and output resistance of each load cell. The resistance values need to fall within the load cell datasheet’s tolerance range.
- Make sure that all of the grounding connections on the body of the load cell are secure, tight, and in good shape.
- Assess the environment in which the load cells are installed. Ensure they are protected from extreme temperatures, moisture, corrosive substances, and excessive vibrations.
Environmental conditions
- The temperature and humidity conditions surrounding the weighing device may have an impact on measurement accuracy.
- Maintenance experts advise positioning the weighing instruments far from sources of heat and moisture.
- They must also routinely check the surrounding conditions to make sure they stay inside the limits that are set by the weighing system.
Documentation
- In order to troubleshoot and identify trends in the functioning of the weighing system, it is crucial to maintain accurate records of all maintenance tasks, calibration dates, and any issues or repairs conducted on the system.
- This data should be logged by the weighing system maintenance crew in a logbook or database so that it may be analyzed and reported on later.
Completion of PM maintenance
- After performing any maintenance procedures, you should always calibrate the weighing system
- Make sure that all test equipment, test weights, measuring equipment, and devices are installed in their designated field locations or are returned to their respective locations or specified areas once the PM is complete.
- Check that the PM’s workspace has been kept neatly organized for the weighing system.
- De isolate the weighing system and Remove the barricade and traffic diversion, as well as the weighing system’s isolation.
- After the PM work is finished, make sure the weighing system is secure and functional.
Preventive maintenance checklist
Please click on the link that is provided below in order to obtain the preventative maintenance checklist of industrial platform weighing scale in excel format.
