bgtorque

S7-314C-2 PN/DP DIG IN/OUT Enabling

6 posts in this topic

Hi all

I'm having issues with the Digital Inputs and Outputs.  I have a Digital output that I am clearly switching  on, I can see the output is TRUE when I switch on to monitor the channels, likewise I can switch it off and it goes to FALSE.  If I measure the output directly coming out of the back of the module (I am looking at DO.2, so the third one which is on terminal 24) I get 0.8Vdc, regardless of whether or not I am TRUE or FALSE on that output bit?  cAn anyone guide me as to why this might be the case and how I would go about enabling the module so I get a 24V Digital Output?

I have 24V on terminals 1, 21, 11, 31.  I have 0V on terminals 10, 30, 20, 40.

As I look at the all the modules I have, including analogue IN/OUT's I have no LED's on, other that the CPU RUN and DC5V.  However, all the analogue channels I have configured are working.  I would've thought I should see an array of LED's on indicating channels are in use?  If I connect a wire to one of the DIG IN channels and directly to 24V the LED for that channel goes green.

I am completely new to Siemens and come from an Allen-Bradley CompactLogix background.

Any help would be appreciated.

Thanks.

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Is the LED of that output ON?

Did you notice that Siemens work with PNP not NPN?

Is the address that you monitor on software same address as you check on hardware?

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No, the output LED is not on when the output is high or low (True or False).

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Also, yes, its the same address i'm looking at.

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The DIG OUT tag is setup as %Q136.2 and the output enable bit is also set to %Q136.2

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Ok, thanks for the suggestions.  I have looked at my Main Routine [OB1] and I have a couple of networks.  I have dragged each program block on the networks.  When I go online and monitor the Main Routine [OB1] a number of the program blocks are good and highlight with the solid green line box.  A few however are highlighted with a dotted blue box, this includes the routine that contains the Digital Output program.  Could this have a potential to disable the 24V output?

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