1794 AENT Comm Loss

one more question
i could just read this final DINT tag value in wonderware. like you said if its a 4 the connection is good any other value its not.

would i need to use a compare instruction in the PLC to compare this value of 4 to turn a coil on & off & read this value into wonderware?
ON=Good
Off=Disconnected

thanks
 
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one more question
i could just read this final DINT tag value in wonderware. like you said if its a 4 the connection is good any other value its not.

would i need to use a compare instruction in the PLC to compare this value of 4 to turn a coil on & off & read this value into wonderware?
ON=Good
Off=Disconnected

thanks

Personally, I would use the compare in the PLC and create an alarm bit in the PLC/Wonderware. Wonderware has built in Alarm servicing of on/off discrete values. You could animate an alarm in WW as well just using the DINT from the PLC (Color = Red when DINT <>4), but then you wouldn't have the alarm built into the WW tag. Analog Tags in WW have Hi/Lo alarm limits, but that would a bit convoluted to do it that way.
 
A quick and dirty method for detecting the connection status of a FLEX or POINT adapter that has a Rack Optimized connection (which is typical):

When you have a 1794 adapter on ControlNet or EtherNet/IP, there is a tag automatically generated for it that gives you 1 bit per slot for the status of any modules that are part of the Rack Optimized connection.

AdapterName:I.SlotStatusBits 0000_0000_0000_0000_0000_0000_0000_0000

If the connection to the adapter is lost entirely, all of those bits go true, which makes the value of the whole DINT type tag = -1.

Learn something new every day. Usually from Ken. Frequently we have our 24V supply connected to one of our 24V inputs (usually the same one supplying the adapter), and 120V connected to one of our 120V inputs in a rack. Getting "24V absence, 120V absence" faults, along with half the other faults is a good clue the rack is faulted. Usually because the 1794-AENT seems to flip out occasionally if a separately energized analog / specialty module doesn't power up at the same time.

true, but you don't have to act like that
A year ago Ones_Zeroresurrected a 5 year old thread without reading, and reported back they were able to get it going. Why did you resurrected it again a year later?
 
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If you're worried about output module behavior in the event of communication loss, you can configure your Flex I/O output cards to behave a certain way when communication is lost. I know this is also the case with 1734 Point I/O, it's my guess that it's this way on all AB output modules.

That's the only way to reset outputs when communications are lost. The processor can't do it.
 
I know this is an old thread but.

I do remember there being some issues with some of the earlier firmware of the 1734 AENT in that it would drop packets in excess and lead to a communications fault.

Not sure if this applies to the 1794 AENT or not Just something to check by reading some of the firmware history and anomalies and corrections.
 
If you're worried about output module behavior in the event of communication loss, you can configure your Flex I/O output cards to behave a certain way when communication is lost. I know this is also the case with 1734 Point I/O, it's my guess that it's this way on all AB output modules.
Hello,
I have a question for the 1794 module properties is possible to adjust the the range in that screen i know you can select the 4-20 and other options.
Im using the studio and have some 1756 and 1794 cards at the controllers tags is the only place i can adjust the output for the scale.
 
Welcome to (participation in) the PLCTalk Forum community !

This is an old thread on a topic that is only slightly related.

Please go back to the top level of the Q&A section, and click the green "Start a New Thread" button above the upper left corner of the main thread list.

Please post what version of Studio 5000 you are using, and some details about the exact FLEX I/O modules you are configuring.
 

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