Nine problems to look out for when using infrared thermometers
1, infrared thermometer should try to set up around some of the "baffle", or even with a thin metal plate to cover up the thermometer.
This can prevent debris staining the pyrometer and some movable parts, and this "staining" will often make the movable part of the movement is not happy, and affect the weighing accuracy. Whether the system has the movement of the phenomenon, you can use the following method to determine. That is, on the scale plus or minus about one-thousandth of the rated load to see if the electronic weighing scale weighing display instrument is reflected, reflected, indicating that the movable part is not subject to "contamination".
2, all leads to the display circuit or lead from the circuit, should be shielded cable.
Shielded cable connection and grounding should be reasonable. If not grounded through the mechanical frame, it is grounded outside, but the shielded wires are connected to each other without grounding, is floating.
Note: There are three pyrometers are fully parallel connection, the pyrometer itself is a 4-wire system, but in the junction box for 6-wire connection. Pyrometer output signal readout circuit should not be able to produce strong interference with the device can be "silicon, contactors, etc.) and there is considerable heat generated by the equipment in the same box, if you can not guarantee that this point, it should be considered to set up a baffle between them to isolate it, and in the box placed in the body of the fan. Electronic circuits used to measure the output signal of the thermometer, should be configured as far as possible, independent of the power supply transformer, rather than share the same main power supply and contactors and other equipment.
3, infrared thermometer should be used hinged copper wire (cross-sectional area of about 50mm2) to form an electrical bypass to protect them from welding current or lightning hazards. Pyrometer use, must avoid strong thermal radiation, especially unilateral strong thermal radiation.
4, electrical connection preparation (such as pyrometer signal cable, not and strong power line or control line parallel arrangement (for example, do not put the pyrometer signal line and strong power line and control line placed in the same pipe). If they must be placed in parallel, then, the distance between them should be maintained at more than 50CM, and the signal line with a metal pipe sleeve.
5, as far as possible, the use of automatic positioning (reset) role of the structure of the accessories, such as ball bearings, joint bearings, positioning fasteners.
They can prevent some lateral force acting on the pyrometer. To be clear: 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 some container scales, i.e., they are not caused by mechanical installation. Some scales must be connected to some accessories on the scale body (such as container scales feeding pipes, etc.), we should let them in the direction of the thermometer loading spindle as soft as possible, in order to prevent them from "eating" the thermometer's real load together and cause errors.
6, to take lightly put especially by the alloy aluminium elastomer made of small capacity pyrometer, any impact, fall, on its measurement performance may cause great damage. For large-capacity infrared thermometer, in general, it has a large self-weight, so the requirements in the handling, installation, as far as possible, the use of appropriate lifting equipment (such as hand-operated hoists, electric hoists, etc.). Installation of the thermometer base mounting surface should be flat, clean, without any oil film, adhesive film and so on. The mounting base itself should have sufficient strength and rigidity, generally require higher than the strength and stiffness of the pyrometer itself.
7. Although the infrared thermometer has a certain overload capacity, it should still be prevented from overloading the thermometer during the installation of the weighing system. It should be noted that even a short period of overload may cause damage to the pyrometer.
During installation, if necessary, the pyrometer can be replaced by a pad of the same height as the pyrometer, and then, when it arrives, the pyrometer can be replaced. In normal operation, the pyrometer should generally be set up to protect the mechanical structure of the overload. If the thermometer is fixed with a screw, a certain tightening torque is required, and the screw should be screwed into the thread depth. Generally speaking, the fixed screw should be a high-strength screw.
8, regardless of the circumstances, the power line and the control line should be twisted together, the degree of integration of 50 rpm / m. If the pyrometer signal line needs to be extended, it should be a special sealed cable junction box. If you do not use such a junction box, and the use of cables and cables directly to the butt (tin soldering end), it should be sealed against moisture to pay special attention to, connected to the insulation resistance should be tested, and need to meet the standards (2000 ~ 5000M), if necessary, should be re-calibrated pyrometer. If the signal cable is very long, and to ensure high measurement accuracy, should consider using a cable compensation circuit with a relay amplifier.
9, level adjustment
Level adjustment has two aspects. One is a single pyrometer mounting base installation plane to adjust the level of the level, on the other hand, refers to more than one pyrometer mounting base mounting surface to try to adjust to a level surface (with a level), especially the number of pyrometers more than three of the weighing system, it should be more attention to this point, the main purpose of doing so is to make the load borne by the pyrometer is basically the same. The loading direction of each kind of electronic weighing infrared thermometer is determined, and when we use it, we must load the load in this direction. Lateral force, additional bending moment, torque force should be avoided as much as possible.
