How do I wire this Rosemount temperature sensor?
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How do I wire the Rosemount 644 temperature transmitter?
This post was last edited by xxkhc on 2018-5-16 at 14:00. It’s in the manual; I’m providing it to you.
If temperature compensation is to be used, does that mean 1 and 2 need to be connected with a shielded cable, 3 and 4 also need to be connected with a shielded cable, and a two-wire 4-20mA output signal cable can be used to connect to the power supply?
I’m talking about the 644H – single input
This post was last edited by xxkhc on 2018-5-17 at 22:07. It shows 644H–single input; didn’t you see that? 2(-) and 3(+) are connected to the thermocouples, while 1 and 4 remain unused. C+ is connected to the positive terminal of the 24V power supply, while C- serves as the output terminal for a 4-20mA current; the positive terminal of the load is connected to C-, and the negative terminal of the load is connected to the negative terminal of the 24V supply.
Just follow the connections shown in the diagram; pay attention to the positive and negative sides. For wire 2, it’s 3+2-; for wire 3, it’s 12-3+; for wire 4, it’s 12-. 34+
My diagram shows only two wires, 2 and 3; I’m unable to upload it. Is it a two-core signal wire used to connect the positive and negative terminals of the power supply, with a compensation wire then being used inside the transmitter to connect 3 to the positive terminal and 2 to the negative terminal?
As you said, I just need to bring in a two-core wire: connect the positive terminal to C+, C- to 3, and the negative terminal to 2. Is that right? How is temperature compensated, by using a three-wire configuration?
644 If no requirement is specified during production, the factory configures it using a 4-wire PT100 setup. You can check the 644 label; it indicates how it was configured at the time of manufacture. The type and wiring of the sensors actually connected must be consistent with the internal configuration of the transmitter; otherwise, the output will be at its maximum. As for how to wire it exactly, there are simple instructions on the module; you can take a look. As for the compensation you mentioned, I’m not very familiar with it; there shouldn’t be any need for compensation, right?
After reading your reply, it seems you still haven’t figured out what kind of wires need to be connected. The wiring for the 644 involves two aspects: one is the wiring between the temperature sensing element and the 644, and the other is the wiring for the 4-20MA current signal output. Are you asking about the wiring for that one? The two types of wiring must not be confused!
It’s probably because I didn’t explain myself clearly enough. What I mainly want to know is how to connect the 4-20mA signal line, whether it’s necessary to connect this signal line to thermocouples 2 and 3, and how to perform temperature compensation only for thermocouples 2 and 3.