Navigation:  Tutorials > Measurement tutorials > Temperature > DEWESoft 7.0  data acquisition, processing, analyzing and storage software PAD channel setup

Another way to measure temperature is with the PAD-TH8-P module. This module sends the data through a serial interface, and is therefore slower, but we can have eight channels per slot. There are different connectors blocks available for the measurement of thermocouple J, K and T types and RTD sensors. The connector blocks are automatically recognized by the module, so the range is already set correctly. The only thing left to do is to set the channels the user would like to use to Used. We can also define averaging, which will make curve smoother, but it will also reduce the response time.

The number of averages decreases the noise, but also decreases the speed. With 1 average ,  the user will have a 6 Hz update rate, and with 4 averages there will be a 1.5 Hz update rate. On the other hand, if there are more modules, the readout speed will not be more than 1 Hz, so it makes sense to switch to 4 averages if acquiring more PAD modules.

If we connect the thermocouple block, then the type of connector block is automatically recognized and the measurement range is adjusted to the real range.

 

If we connect the RTD connector block, types of sensors connected to the module need to be specified. Supported sensors are Pt100, Pt200, Pt500, Pt1000, Pt2000 and Ni120. Sensor types cannot be mixed on the module.

 

Also note that measuring temperature with a Pt100 or similar sensor is based on simple resistor measurements. Keep in mind that the resistance of the lead wires will influence the measurement result. The resistance changes with the temperature, the length and the diameter of the lead.

The 4-wire connection will completely remove all measurement errors caused by lead resistance.

Using 2-wire connection, the lead resistance will not be eliminated at all. Especially when using long and thin wires from the PAD-CB8-RTD to the temperature sensors, the measurement result will be distorted.

The 3-wire connection will also compensate the lead resistance completely if all three wires have the same diameter and length. In that case, it is safe to assume that the lead resistance of all three wires is the same. Therefore, the resistance of only one wire has to be measured for eliminating the lead resistance influence.