It is based on that temperature change of material results in change of its resistance. When resistance value changes, the working instrument will display relevant temperature.
分度号
Graduation | 测温范围
Measuring Range | 精度等级
Accuracy Class | 允许偏差
Tolerance |
Pt100 | -200～+500 | A级 | ±(0.15+0.002)ltl |
| |
B级 | ±(0.30+0.005)ltl |
Pt100
Insulation resistance between electrode and outer tube is no less than 100MΩunder condition that ambient temperature is 15~35℃, relative humidity is no more than 80%, and test voltage is 10~100V (D.C.).
Thermal Response Time
When step change of temperature happens, τ0.5 is used to indicate the time for current output signal of instrument changes into 50% of the step change value.
Nominal Pressure
It generally refers to the sustainable static pressure from outside on protection tube without breakage. It concern not only material, diameter & wall thickness of protection tube, but the structure, mounting way, insert length, flow speed and category of tested media as well.
Installation & Operation
Ambient Conditions
Ambient Temperature:-25～80℃
Relative Humidity：5﹪～95%
Mechanical Shock: f≤55Hz, <0.15mm
There shall be no corrosive medium on components in ambient air.
Installation close to boiler door or heated object shall be avoided. Contact of wiring box with container wall tested medium is forbidden. Strong shock in installation place shall be avoided as possible as it could.
The tube is pre-mounted in manufacturing the device, therefore type and material of the tube shall be selected in designing the device according to temperature, pressure, flow speed and other factors of the medium to be tested. The key lies in that strength of the tube shall remain no lower than the device itself, or even higher than the latter.
The tube could be mounted through welding, flange connection, threaded connection or other ways. Nevertheless, strength of welding or connection shall be ensured. If necessary, both threaded connection and welding shall be adopted to ensure operation safety.
Wire Connection&Wire Selection
Generally, copper conductor shall be adopted for connection wire of thermal resistance. Cross-section area of the wire to be selected depends on distance, and insulation materials and different protections of the wire to be selected depend on environment conditions.
No. | Technical Trouble | Possible Reason | Solution |
1 | Low or instable display value of measuring instrument | Electricity leak of inner electrode of thermocouple
(Poor insulation of armored thermocouple)
Moisture or metallic filings on wiring stand or short circuit of thermal resistance | Replace armored thermal resistance Clean wiring stand and dry it or replace thermal resistance |
2 | Maximum display value of measuring instrument |
| Check wiring and thermal resistance with multi-meter
.Repair for wiring break-off
Replace it for break-off of thermal resistance |
3 | Minimum display value of measuring instrument | Short circuit of thermal resistance | Check with multi-meter for short circuit position, then repair or replace it
Renew wire connection |
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