Micrologix Embedded Analog I/O - Need Data File Maps

wildcatherder

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The Micrologix Programmable Controllers - Instruction Set Reference Manual describes analog input data files for two different modules and analog output data files for two different modules. It does not describe what a data file looks like for the Embedded Analog I/O.đź““

Would someone please point me to a description of the Embedded Analog Data Files, both input and output? Maybe it is the same as one of the types shown but I could not tell from the descriptions whether that is the case

Searching for the words "embedded" "analog" "input" "output" "data" and "files", in any combination produces too many results to be helpful.
 
Which controller are you working with ?

For the MicroLogix 1400 controller, for example, I found the information in the User Manual (1766-UM001) in the Specifications for the analog input channels.

0-10 V is represented as 0-4095 counts.

For the MicroLogix 1400 controller, the analog input channels are addressed as I:0.4,5,6,7 and the outputs are O:0.4 and O:0.5. I found these in the default descriptions in the Input and Output data tables, though I'm sure they are somewhere in the User Manual or Instruction Set Reference.

ml1400analog.PNG
 
I did find the information you suggested. However, these are not "maps" of the data input/output files.

For instance, in the 1762-IF2OF2 input data file, it shows that, in Raw/Proportional Format, the first three bits are Don't Care.

The 1762-IF4 the first 14 bits for input data and bit 15 as a sign bit.
These are the details I am looking for.
 
The answer is 0-4095 as shown in Eddie Willers post. Also see PDF below.
Its 0-4095 raw data for both input and output.
 
I have no idea. Why not apply 10 volts and then look at the address in it's binary form. Curious, why is this important to you. My GUESS is it just uses the first 12 bits, nothing more to it.
 
Maybe you're having trouble with the way Micrologix addresses work...

The address I:0.4 in this case is a 16 bit integer. The usable range is 0-4095 or 12 bits. Bits 12-15 are always zero.

edit: As usual, Mickey types faster.
 
Why do I want to know what the data is doing?

If the last bit is a sign bit or 0v/Full Range bit?

If the first three bits are zero?

Because I am trying to program some meaningful first steps.
Because if it matters for the modules, it matters for embedded points.
Because I don't, at this point, have a bunch of equipment sitting on my desk where I can feed in a calibrated value and get an answer.

Because I'm trying to follow the manual and it worries me that information appears to be missing.
 
Which controller are you working with ?

For the MicroLogix 1400 controller, for example, I found the information in the User Manual (1766-UM001) in the Specifications for the analog input channels.

0-10 V is represented as 0-4095 counts.

For the MicroLogix 1400 controller, the analog input channels are addressed as I:0.4,5,6,7 and the outputs are O:0.4 and O:0.5. I found these in the default descriptions in the Input and Output data tables, though I'm sure they are somewhere in the User Manual or Instruction Set Reference.

Can we use 4-20 mA signal in these analog inputs ? @ Eddie Willers
 
You could convert 4-20 mA to 2-10 volts with a 500 ohm precision resistor.

At 20mA - Ohm's law: 10 (E) = .02 (I) x 500 (R)
At 4 mA - Ohm's law: 2 (E) = .004 (I) x 500 (R)
 
Last edited:
I should have added you’ll lose a bit of accuracy from the input being parallel with the resistor, and accuracy of the resistor.

Analog inputs are around 200 K ohm input impedence which makes the resistance with a perfect 500 ohm resistor about 498.8 ohms, making 20 mA about 9.98 volts.

It’s not optimal but if you don’t need extreme precision, it will work.
 
Why do I want to know what the data is doing?

If the last bit is a sign bit or 0v/Full Range bit?

If the first three bits are zero?

Because I am trying to program some meaningful first steps.
Because if it matters for the modules, it matters for embedded points.
Because I don't, at this point, have a bunch of equipment sitting on my desk where I can feed in a calibrated value and get an answer.

Because I'm trying to follow the manual and it worries me that information appears to be missing.

An analog value is just that...............an analog value - usually displayed and used as an integer.

Sounds like you are trying to do something clever with the value of the analog input - can we ask why?
 

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