Several Issues to Pay Attention to in the Use of Infrared Thermometers
1. Try to set up some "baffles" around the infrared thermometer, and even cover the thermometer with thin metal plates.
This can prevent impurities from contaminating the thermometer and some movable parts, which often cause discomfort in the movement of the movable parts and affect the weighing accuracy. The following methods can be used to determine whether the system is experiencing discomfort during movement. Add or subtract approximately one thousandth of the rated load on the weighing platform to check if the electronic weighing display shows any response. If there is a response, it indicates that the movable part is not contaminated.
2. All wires leading to or from the display circuit should be shielded cables.
The connection and grounding point of the shielding wire should be reasonable. If it is not grounded through the mechanical frame, it is grounded externally, but the shielding wires are not grounded after being connected to each other, which is floating.
Note: Three thermometers are connected in full parallel. The thermometers themselves are 4-wire, but they are replaced with 6-wire connections inside the junction box. The output signal readout circuit of the thermometer should not be placed in the same box as devices that can cause strong interference (such as silicon control and contactors) and devices that generate considerable heat. If this cannot be guaranteed, barrier isolation should be considered between them, and a fan should be installed inside the box. The electronic circuit used to measure the output signal of the thermometer should be equipped with an independent power supply transformer as much as possible, rather than sharing the same main power supply with devices such as contactors.
3. Infrared thermometers should use hinged copper wires (with a cross-sectional area of approximately 50mm2) to form electrical bypasses to protect them from hazards caused by welding currents or lightning strikes. During the use of a thermometer, it is necessary to avoid strong thermal radiation, especially on one side.
4. In terms of electrical connection, preparations should be made (such as the signal cable of the thermometer, which should not be arranged in parallel with the high-voltage power or control line (for example, do not place the thermometer signal line, high-voltage power line, and control line in the same pipeline). If they must be placed in parallel, the distance between them should be maintained at 50CM or more, and the signal lines should be covered with metal tubes.
5. Try to use structural accessories with automatic positioning (reset) function, such as spherical bearings, joint bearings, positioning fasteners, etc.
They can prevent certain lateral forces from acting on the thermometer. It should be noted that some lateral forces are not caused by mechanical installation, such as lateral forces caused by thermal expansion, lateral forces caused by wind, and lateral forces caused by vibration of agitators on certain container scales, which are not caused by mechanical installation. Some scales have attachments that must be connected to the scale body (such as the feeding pipeline of the container scale). We should make them as soft as possible in the direction of the loading spindle of the thermometer to prevent them from "eating" the true load of the thermometer and causing errors.
