Hi-
Doing my first hardware/software implementation with a smart motor. While setting up hardware, could not find a specific reference to guide wiring of universal discrete inputs on optional isolated 24V IO. I followed the example given in the user guide on page 57 however this drawing is specific to the 7 standard IO (unisolated 0-5V). The inputs are wired through a NO switch to the 24VDC common and are non-responsive to button press. I believe my error was that these should be wired from the NO switch to +24VDC. Can you confirm?
Thx in advance
You are correct. The Isolated 24V I/O is sourcing, so the inputs will turn on when they see 24VDC.
CS- thanks, reworked the cable assembly last night to expose an unused input and tested there- works perfectly. Reworked IOs of consequence and suddenly had a somewhat running application- now for the debug. Thanks very much for your confirmation. On a related note- do you know of a comprehensive set of documentation that reflects current hardware/software? (I'm now finding code differences in the user guide examples). Thx!!!
note: the term 'sourcing' here I find confusing- was taught that sourcing meant a +VDC supply was connected and that a DC common was required to complete the circuit- sinking is the opposite (common connected, need +VDC). Referenced NI last night to check and they agree, here's the link- http://digital.ni.com/public.nsf/allkb/a10122c63a7f5cfe86256b4c007491dd. Operated on memory and the drawing of the 5V IO which indeed shows a sourcing arrangement for the design of the cable assembly that was non-functional. My memory here and NI's input both indicate that this is a sinking input- how are you drawing the 'sourcing' conclusion? Bottom line the device is fully functional now and this is for my own re-education! Thx...
You have a Class5 motor, so the users guide on the main page under Support is the one you need.
The definitions of Sinking and Sourceing have been a long going debate between PLC manufacturers. I have always followed the rule that if the input turns on with plus voltage, then it is sourcing.
The inputs are sourcing. They require 24V to turn on. Ok. How about the outputs. Are they sourcing or sinking. A output that is turned ON will have 24V on it and an output that is turned OFF will have 0V. Is this correct?
You are correct.