Temperature Module for 1746-NI4/B

[Automater]

Hello all.

I have a 1746-NI4/B and I would like to get a cheap temerature module which I could use.

I have found this on ebay:

http://cgi.ebay.es/ws/eBayISAPI.dll?ViewItem&item=191436133405#ht_1113wt_1158

But, I do not know which resistor goes with it. I have contact the seller.

Does anyone know of another solution please?

Thank you

 

[danw]

The printed label says that it uses a platinum 100 RTD sensor (Pt100). Is that what you mean?

Although one might expect that the signal/power connects to the top two terminals and a 3 wire RTD would connect to the lower three terminals, the actual connections appear to guesswork. It is not clear from the label which terminals the resistor of a 3 wire RTD connect to.

 

[Automater]

The printed label says that it uses a platinum 100 RTD sensor (Pt100). Is that what you mean?

Although one might expect that the signal/power connects to the top two terminals and a 3 wire RTD would connect to the lower three terminals, the actual connections appear to guesswork. It is not clear from the label which terminals the resistor of a 3 wire RTD connect to.

Hello, This is what they sent me.

Would this be the sensor needed in question? http://www.ebay.co.uk/itm/Platinum-...301241?hash=item51c7415f79:g:5bMAAOSwzhVWqcZq

 

[danw]

You need to specify that you are ordering a PT100A or B.

You need to make sure your analog input can handle 1-5Vdc - this is not a 2 wire loop powered 4-20mA (current) transmitter, it is a 3 wire 1-5Vdc transmitter.

It has no lead wire compensation so the length of the copper lead wires will contribute a resistance to the temperature reading which will be a constant offset error. That's the nature of 2 wire RTD measurements.

 

[Automater]

You need to specify that you are ordering a PT100A or B.

You need to make sure your analog input can handle 1-5Vdc - this is not a 2 wire loop powered 4-20mA (current) transmitter, it is a 3 wire 1-5Vdc transmitter.

It has no lead wire compensation so the length of the copper lead wires will contribute a resistance to the temperature reading which will be a constant offset error. That's the nature of 2 wire RTD measurements.

Hello,

So something like this? http://www.ebay.co.uk/itm/Platinum-...301241?hash=item51c7415f79:g:5bMAAOSwzhVWqcZq

Thank you very much.

 

[Automater]

Ok,

So this is how I would set it up?

I would change the 1746-NI4/B from voltage to current sensing.

Thank you

 

[Automater]

Na

 

[danw]

The wiring on the label in post #3 (3 wire, 1-5Vdc output) does not match the functionality of the wiring in post #6 (4-20mA output). Without a wiring instructions it isn't clear whether the 2nd transmitter is a 2 wire or a 3 wire, or which terminals are which.

The 2nd link you sent is a link to the same RTD as the first, it is not a link to a different transmitter.

The RTD is NOT wired according to the label on the 2nd transmitter. The PT100 rectangle (resistor) goes across the right two terminals, the odd colored wire on the far right terminal. (in the label diagram it goes where the rectangle with arrow through it connects).

The remaining same-colored wire goes to the terminal on the left.

Assuming that the 2nd transmitter is 2 wire, loop powered, then the polarity for the receiver (recorder/display 4-20mA acquisition) is backwards (in your diagram). The DC power supply is wired correctly.

Can't answer wiring questions without the wiring diagram.

 

[ASF]

...Assuming that the 2nd transmitter is 2 wire, loop powered, then the polarity for the receiver (recorder/display 4-20mA acquisition) is backwards (in your diagram)...

It looks OK to me? Positive of DC supply to positive of TX, negative of TX to positive of PLC, negative of PLC to negative of DC supply?

You're correct about the RTD side wiring though.

 

[danw]

My bad. I stand corrected. The loop wiring in the 2nd diagram is correct.