Using Wonderware to access MicroLogix 1100's via Radio?

[Darksabre]

if the integer in the plc is always 1 then wonderware reads the 1 and holds that value. wonderware isnt going to change it to zero unless it sees zero in the plc.

why dont you use the comm status functions that are built int the driver. update interval and comm status should be useful. you can also look at error counts if you want.

Hmm, but the wonderware script successfully sets it to a zero every time it reads from the PLC. I'm watching the integer change on the screen.

Well anyway, how do I access the comm status values of the driver as tags in wonderware?

 

[diat150]

Hmm, but the wonderware script successfully sets it to a zero every time it reads from the PLC. I'm watching the integer change on the screen.

Well anyway, how do I access the comm status values of the driver as tags in wonderware?

you said that the tag in the plc is always 1 right?

anyway, $SYS$Status is the comm status, IO discrete, 0 = alarm 1 = normal

$SYS$UpdateInterval is the update interval and it is IO real. It will give you the amount of seconds since the last poll in milliseconds.

If you look in the drivers manual it will give you all of the built in stuff and how to set it up.

 

[Darksabre]

Right, the tag is always a 1 in the PLC, so every time wonderware polls that PLC, it will see a 1, reset the timer, and set the tags value from 1 to 0 - which is what appears to happen just fine. The only strange thing is that when the serial cable is disconnected, it pulses from a 0 to a 1 every ten seconds w/o any PLC connected.

Thanks, I'll try out those system status tags you gave me instead.

 

[Darksabre]

you said that the tag in the plc is always 1 right?

anyway, $SYS$Status is the comm status, IO discrete, 0 = alarm 1 = normal

$SYS$UpdateInterval is the update interval and it is IO real. It will give you the amount of seconds since the last poll in milliseconds.

If you look in the drivers manual it will give you all of the built in stuff and how to set it up.

I've been looking through the driver's help file, and it says this: "Enter the following DDE reference formula in the appropriate place in your client: =DASMBSerial|ModiconPLC!$SYS$Status"

Not sure how to assign that to a tag or what access name to use. Sorry for all of these super noob questions. I dont usually deal with this part of the project! Thanks!

 

[diat150]

just make a new tag in ww called PLC1commstatus or whatever, make it a discrete IO tag, use the access name of whatever plc you want to monitor, and then set the item as $SYS$Status

 

[Darksabre]

just make a new tag in ww called PLC1commstatus or whatever, make it a discrete IO tag, use the access name of whatever plc you want to monitor, and then set the item as $SYS$Status

Ohh, that is fantastic - works like a charm. Thank you!

UpdateInterval seems to display a 5000 constantly though. Even if I unplug the serial cable.

 

[diat150]

sorry, you can use that one to set the poll rate.

$SYS$MaxInterval is what you use to see the actual poll rate.

if you look in DASMBSERIAL.PDF underneath item names, then DAServer Standard System Items you will find all of the things you can look at and what they do.

 

[Darksabre]

Success!!!

Amazingly, I have everything working together. I put together a little test setup in my office using the plc's and radios along with the wonderware computer - everything worked flawlessly.

Man, I didn't think I'd ever figure this one out when I was first starting out, but you helped me along the way. I definitely appreciate this website and its great members like diat150. Thank you again man!!

Hopefully everything will work once they're in the field with big yagi's and a bit of delay. *fingers crossed*

 

[diat150]

shouldnt have any issue unless it is a path issue between radios. I use mds radios with this same setup all of the time.

 

[Firejo]

You will have problems with Modbus RTU over the MDS radios unless they have a "Modbus" setting like Data-Linc or FreeWave does

 

[diat150]

You will have problems with Modbus RTU over the MDS radios unless they have a "Modbus" setting like Data-Linc or FreeWave does

absolutely wrong. Ive been using mds radios with modbus for 10 years and never had an issue. ive fooled with some freewave radios also and dont remember any setting for "modbus".