What Analogs are sent through Streamed Data from OptoMMP


The OptoMMP Protocol Guide (#1465) says this about streamed data:

Analog Engineering Units data for 64 channels (float). Includes the first four channels on 16 analog modules; if an analog module has more than four channels, data is included for channels 0-3 only.

I am confused about what this means. Specifically:

  1. Does this include both Analog Input and Analog Output modules?
  2. Does the phrase Engineering Units refer to the scaled values, or the actual value of the scaled value of the analog?

Suppose I have four I/O modules with Analog Input and Analog Outputs, all 0-10vdc, scaled to 0-1000 real-world-units (rwu)

Module 0: SNAP AIV-i (2 AI, named AI_0a and AI_0b)
Module 1: SNAP AOV (2 AO, named AO_1a and AO_1b)
Module 2: SNAP AIV-i (2 AI, named AI_2a and AI_2b)
Module 3: SNAP AOV (2 AO, named AO_3a and AO_3b)

Suppose the AI values are all 3vdc (300 rwu) and the AO values are all 4 vdc (400 rwu).

Will the data portion of the streamed data contain –

Unscaled (i.e. 3.0, 4.0) or scaled (300.0, 400.0) values?

values for both AI and AO modules:
AI_0a, AI_0b, AO_1a, AO_1b, AI_2a, AI_2b, AO_3a, AO_3b

AI modules only:
AI_0a, AI_0b, AI_2a, AI_2b

AI with 0’s for the AO modules
AI_0a, AI_0b, 0.0, 0.0, AI_2a, AI_2, 0.0, 0.0

or something else?

  1. Yes, includes both inputs and outputs.
  2. Engineering units are the real world units that you defined, so by that description you will get your 300, 400 values, not the 3vdc, 4vdc.