1756-IB32 ControlLogix Input Module

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Thread Starter

Forat

Dear Control community,

I am studying about ControlLogix IO modules 1756-IB32, with the respective link to the picture below.

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1756-um058_-en-p.pdf

Page 142 1756-IB32

In the IB32: Voltage from IN-0 (10-30V) passes through the Current Limiter, the LED, and finally through the GND-0 Ground.

The LED will emit light to the Optical transistor's gate terminal, and it will pass the current from the to the collector terminal (+5V) to the ControlLogix Backplane Interface and into the Display.

This is what I don't understand, how come when IN-0 is ON, the IO module (IB32) will be powered on, do it's function (sending information to Processor, sending data to display...etc...), and if IN-0 is OFF, the Module will be off.

I always thought that, there is a power supply that provides a signal and another power to the IO modules.

Kindly help me on this matter.

Thank you in advance.
Forat
 
The module will be powered from the backplane regardless of the voltage/logic state of IN-0. Which is what the simplified schematic is showing, so the transistor side of the opt-isolator is always active.
 
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