Analog Input/Output

I have a 1746 - N1041 A in a SLC Fixed style controller. A Moore Industries RBT transmitter for my 3 wire RTD. I would like to hook the transmitter up to the PLC to monitor temperature. What instruction set would I start with to get a value to show up in RSLogic? The SCL instruction set is grey'd out. That is the one I thought I should start with.

I'm allso not sure if I have to hook 5v or 24 volts to the transmitter....I know the fixed controller has a power source but I wanted to use external power. Is any body familiar with these units? I have a 24V power supply.

Thanks for any advice or pointers in what direction I should go to learn how to do this....

RBT manual here
http://www.miinet.com/custservice/manuals/rbt_man.pdf
has wiring info, but you'll need to decode the model number.

You'll need to "roll your own" SCL/SCP instruction using math functions. If you're familiar with y=mx+b, you can implement that. I don't have a SLC500 fixed IO available that I can play with, but your math should look something like this:

Notes:
IN_MIN = minimum value the input register can reach, raw from input module
IN_MAX = maximum value the input register can reach, raw from input module
IN_RAW = input register, raw from input module
OUT_MIN = minimum value the output register can reach
OUT_MAX = maximum value the output register can reach

You may need to do some limit checking to make sure your values are within reasonable ranges.

If your input/output ranges start at zero, you can simplify the code significantly:

After you find the model number tell us the input e.g. 4 to 20ma and what it represents
e.g. 0 to 150 deg F or C. We can then help you with scaling to engineering units.
Without the scaling instructions you will have to do the math yourself, see picture below for data format info for different inputs.
Also can you tell us which SLC you have (complete catalog number please)

"You'll need to "roll your own" SCL/SCP instruction using math functions" could you please elaberate on this a little. I understand the math functions....I'm having a problem in choosing the SCL/SCP instruction set. I can find the SCP instruction set in the menue but it is grey'd out so I can't drag it down. I'm asuming once you drage it down you can link it to the input card like "I:1.0/0" meaning Input card slot 1, input O. Am I correct? If so I have to figure out why the SCP is grey'd out. Not an option.

Angus

The convenient Scale with Parameters (SCP) instruction isn't supported by the 1988-vintage Fixed SLC controller.

Fortunately, a simple linear equation "Y= mX +b" is straightforward even in ladder logic.

To figure out the slope and offset, you need to know what values will be in the SLC data table to 4 mA and 20 mA (the analog module user manual) and what mA values will be generated by what temperatures (the Moore user manual).

Doing this math in a fixed SLC requires that you know not only the equation but also the SLC operating system and how it handles integer overflows.

Attached is a PDF of an example of how to do this using the S:13 and S:14 "Math Register" and the Double Divide (DDV) instruction.

All the actual values are assumptions until you know what the range of degrees is for the 4-20 mA output of the RTD Transmitter.