Signal generator verification temperature
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I used a signal generator to provide an output resistance for a temperature transmitter in place of the thermal resistor. This method won’t work. What is the reason for this? The temperature transmitter is three-wire. I shorted out the BB.
The temperature control gauge being tested currently can use a signal generator, but a temperature transmitter cannot
I am also using the output of a process calibrator, which provides a resistance value, to replace the thermal resistor and use it as the input value for the temperature transmitter. The temperature transmitter does not output any value; I don’t understand why. I hope the experts in the group can help me figure this out. Thank you.
Sure, a transmitter isn’t a human being and can’t tell what you’re connecting; what’s important is that the sensor configuration be correct and 24V power be supplied in order to carry out measurements
There is no problem if a signal generator outputs a resistive signal, but many signal generators output current or voltage signals. First, determine whether the output signal is a resistance signal; if so, then check the temperature transmitter.
In this case, use a rheostat box; do not use a signal generator. This is because the loop detection circuit of the transmitter generates voltage and current signals on the thermistor wire in addition to the resistance value, and these signals are absorbed by the signal generator. Since the transmitter cannot be identified, there is naturally no response.
I can be sure that the output signal is a resistive signal, and the multimeter can measure the resistance value; however, it’s useless for feeding it to a temperature transmitter.
Well, thank you. But the thermistor signal simulated by the signal generator cannot be used as an input for temperature transmitters; so what is its purpose then?
It has been determined that the temperature variation input signal is a resistive signal; check whether the output circuit of the temperature transmitter is properly wired. Generally, it is a two-wire system for temperature measurement, with the power line and the signal line sharing the same connection – verify that there are no breaks in the connections； If there are no issues with the input and output connections of the temperature transmitter, if the input signal and power supply are fine, and if the instrument used to measure the output signal is working properly, then there must be a problem with the temperature transmitter itself; try replacing it.