PT100 How to measure good or bad
 

PT100 Temperature sensor is a instrument that converts temperature variables into standardized output signals that convert temperature variables into can be transmitted. It is mainly used for measurement and control of temperature parameters of industrial process. The transmitter with a sensor is usually composed of two parts: sensors and signal converters. The sensor is mainly thermocouple or the thermal resistance; the signal converter is mainly composed of measurement unit, signal processing and conversion unit (because industrial thermal resistance and thermocouple score table is Standardized, so the signal converter is also known as transmitter ) when it is an independent product. Some transmitters add the display unit, and some also have on -site bus functions. We mainly talk about this article to check the quality of the PT100 temperature sensor with a multimeter. Let's take a look.

The characteristic of PT100 thermal resistance sensor is that at 0 ° C, the resistance of 100 ohm has a decreased temperature at a low temperature of 100 ohm, and the temperature high resistance value rises. Use a multimeter to measure good or bad.
You can first interrupt the PT100 wiring in the loop, and then measure its resistance value with a multimeter's resistor (200 ohm;). However, the measurement results can only judge the good or bad of PT100 temperature sensor , and cannot be used as a basis for verifying its accuracy.
The resistance value of the PT100 temperature sensor at 0 ° C is 100. As the temperature increases the resistance value, the specific corresponding score table.
1. The temperature range of the PT100 thermal resistance is t = 0 ~ 100 degrees, its output is i = 4 ~ 20mA, and the relationship between I and T is i+(4/25)*T
Such as t = 0 degrees I = 4mA, i = 100 degrees I == 20mA, at = 25 degrees when i = 8ma
2. Remove the PT100 thermal resistance and place it in a water container. The changes in the indicator value of the current marker, such as the change in the formula (1), this thermal resistance is good. The change of the change, this thermal resistance is bad.

1. For the two -line type:

Just two leads, the directly measured, its resistance is about 110 ohms.

2. For Third Line < /u> formula:

Its lead is 1, 2, and 3, respectively.

Among them: between 1 and 2, between 1 and 3, the resistance value is about 110 ohms; the resistance between 2 and 3 is 0.

3. For Fourth Line < /u> formula:

Its lead is 1, 2, 3, and 4, respectively.

Among them: between 1 and 2, between 1 and 4, between 3 and 2, between 3 and 4, the resistance value is about 110 ohms; between 1 and 3, between 2 and 4 0.