question about 1762-If2Of2 analog module

Hey all,


Been working on a little project using a Micrologic 1100,
Just added this 2-in/2-out analog module (1762-If3Of2)to my project, and a bit confused by the specs.


Specification page says the outputs are 12 bit (4095)
but another page is showing 15 bit (32760) for "raw/proportional" output, or 14 bit (16383) for "scaled for PID" output.
Which I have selected as raw/prop in the I/O config for the module.


I'm using the scale with parameters (SCP) function to drive a 0-10v output, but unsure about the scaled max, is it 4095 or 32760?



Can anyone help me understand this?


JohnR

See pdf for data format..

note..10volts is equal to 31200 raw data for Raw/Proportional Format and 15600 for Scaled for PID.

See pdf for 12 bit resolution..
Note the first three bits for the Raw/Proportional are reserved leaving bit 3-14 for the data (12 bits)
The first 2 two bits for the scaled for PID are reserved leaving bits 2-13 for the data ( 12 bits)

Don't ask why they did this, I don't know. Maybe the AB guru's will.

Hilarious.

Might seem hilarious, Siemens did the same thing but the 3 LSB's were used for diagnostic error bits, many people used the whole word the 3 bits did not make a huge difference as these would only be active if a problem existed. the way to get rid of them for the value was to right shift 3 places.

I think A/B did it so that you could get away with not having to edit your scaling math if you used different products with different analog resolutions. Although in real life there is still some tiny variation with different cards even of the same part number, so I typically use my calibrator to make them as exact as possible on a case by case basis.