sinking or sourcing

jerry859

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Join Date
Dec 2010
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ky
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Can anyone explain the difference between sinking and sourcing inputs/outputs as it pertains to AB modules. A little confusion between the two. Thanks.
 
sourcing is when positive voltage is triggered with a common negative
Sinking is when you have the positive as a common one and trigger negative voltage on each input/outputs

in America common use is sourcing and i hate to work with sinking modules when i have no other choice, it mixt up the way of thinking and throubleshooting
 
IF you think of it as analog inputs sourcing means it requires a seperate power source and supplies the signal (takes at least four wires to set up, 2 for power and two for input) adn sinking means loop powered.
 
If you have a Allen-Bradley installation instruction manual for a i/o module it has detailed diagrams for sinking and sourcing input and output modules.If you don't have a manual you can download one at
www.rockwellautomation.com/support/ Just look under Product User Manuals and do a new search catalog 1746-ib32.
 
sources are connected to +24 volt and the sinks are connected to 0 Volt.
npn only look to the middle one so it gives amps out.
btw there are totempole with 2 transistors so both sinking and sourcing.
most outputs give a positive voltage when on meaning sourcing output.
 
Can anyone explain the difference between sinking and sourcing inputs/outputs as it pertains to AB modules. A little confusion between the two. Thanks.

For Allen Bradley Sinking and Sourcing is what the module is doing at the terminal. As others have said, in the US Sourcing outputs and Sinking inputs are the most common (Positive signal = 1). A Sourcing output provides a path to the positive voltage at the terminal. A Sinking input will provide a path to common.
 

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