Nine problems needing attention in the use of infrared thermometers
Because the resistance strain infrared thermometer is a robust, dependable, and widespread electromechanical device, it plays a widespread role in the use of electronic platforms. However, in order to assure the correctness of the test, the electronic platforms should pay attention to it in use. So what factors need to be taken into consideration while utilizing an infrared thermometer? The following lists nine considerations that should be made while using an infrared thermometer:
1. Make an effort to surround the infrared thermometer with "baffles," or even cover it with a thin metal plate.
This can avoid material contaminating the thermometer and some movable parts, which frequently causes the movable parts to feel unpleasant and compromises the precision of the weighing. The following techniques can be used to determine whether the system is uncomfortable during movement. To test whether the electronic platform weighing display reacts, add or subtract roughly one thousandth of the rated load on the weighing platform. If there is a reflection, it indicates that the moving portion is not "dirty."
2. Shielded cables should be used for all wires going to or coming from the display circuit.
The insulated wire's connecting and grounding point should be appropriate. It is grounded externally if it is not grounded through the mechanical frame, but the shielded wires are floating after being joined to one another and are not grounded.
Note: Three thermometers are linked in complete parallel. The junction box replaces the 4-wire connection of the thermometer, which is actually a 6-wire connection.It is not advisable to put the readout circuit for the thermometer's output signal in the same box as devices that produce a lot of heat or severe interference (such as silicon-controlled devices, contactors, etc.). It should be taken into account if this cannot be ensured. Install a fan in the box and set up a baffle to separate them. Instead of sharing the same main power supply with contactors and other equipment, the electronic circuit used to measure the thermometer's output signal should, whenever possible, be fitted with a separate power supply transformer.
3. To protect infrared thermometers from the dangers posed by electric welding current or lightning strikes, twisted copper wires with a cross-sectional area of about 50mm2 should be employed to create an electrical bypass. Severe heat radiation must be avoided when using the thermometer, especially strong heat radiation from one side.
4. Make the necessary preparations for the electrical connection (such as ensuring that the thermometer's signal cable is not parallel to a powerful electric power line or control line) (for example, do not put the signal line of the thermometer, the strong electric power line and the control line in the same pipeline). If they must be arranged in parallel, then the signal line should be covered by a metal tube, and the distance between them should be kept above 50CM.
5. Try to use structural accessories with automatic positioning (resetting), such as spherical bearings, joint bearings, positioning fasteners, etc.
They stop some lateral forces from having an impact on the thermometer. The lateral force created by thermal expansion, the lateral force caused by wind, and the lateral force caused by the vibration of the agitator on some container scales are only a few examples of lateral forces that are not caused by mechanical equipment. To prevent accessories from "eating" the temperature measurement, we should make them as soft as possible in the direction of the loading spindle of the thermometer on various scales (such as the feeding pipe of the container scale, etc.). Errors will be brought on by the instrument's actual load.
6. Handle delicately, especially when handling small-capacity thermometers with elastic bodies composed of aluminum alloy. Its measurement performance may suffer significant harm from any hit or drop. It is necessary to utilize the proper lifting equipment (such as chain hoists, electric hoists, etc.) as much as possible during handling and installation because big-capacity infrared thermometers often have a large dead weight. There should be no oil film, glue film, or other obstructions on the mounting surface of the base where the thermometer will be mounted. The installation base should be strong and rigid enough, typically greater than that of the thermometer.
7. The overload of the infrared thermometer should still be avoided during the installation of the weighing system, despite the fact that the thermometer has a limited capacity for overload. It should be remembered that the thermometer could be harmed even temporarily by overloading.
If it is truly essential, you can swap out the thermometer for a block that is the same height as the thermometer during the installation procedure, and then swap out the thermometer again. The thermometer should typically have mechanical structural components for overload prevention when in regular operation. If a screw is used to secure the thermometer, it must be tightened to a specific tension and have a specific screw-in thread depth. In general, using high-strength screws is what causes the fixed screw.
8. The junction degree for the power and control lines should be 50 turns per meter in any case. Use a specific sealed cable junction box if the thermometer's signal line needs to be extended. If a junction box of this type is not utilized and the cable is attached to the cable (soldered end) directly, sealing and moisture resistance should be given special consideration. The insulating resistance needs to meet the requirement (20005000M) after the connection is complete. The thermometer should be recalibrated if necessary. A cable compensation circuit with a relay amplifier should be taken into consideration if the signal cable is very lengthy and high measurement accuracy must be guaranteed.
9. Level modification
There are two parts to level adjustment. One is that the installation surface of the installation base of a single thermometer should be adjusted to a horizontal plane as much as possible (with a level), and the other is that the installation surfaces of the installation bases of multiple thermometers should be adjusted to a horizontal plane as much as possible (with a level), especially for temperature measurement. More consideration needs to be given to this aspect when using a weighing system with more than three instruments.The major goal of this is to roughly equalize the stresses on each thermometer. Each electronic platform infrared thermometer has a certain loading direction, which must be followed when using the device. It is best to keep lateral forces, extra bending moments, and torque forces to a minimum.
