Any way to use SLC tag format in ControlLogix?

[slick_william]

Hi all,

if I remember correctly, there is some way in a ControlLogix (or CompactLogix) where you can sort of map tags into SLC addressing format.

For example, say I want

N7:0 = Tank Level
N7:1 = Pump Temperature
N7:2 = Timeout Setpoint


I seem to remember there is a way where I can create tags in my CPU that actually follow the true SLC address-based format. Then I could map my data back and forth, such as

MOV(TANK_LVL, N7:0);
MOV(PUMP_TMP, N7:1);
MOV(TIMEOUT_SP, N7:2);

We will be doing a PLC conversion from a PLC5/20 to a ControlLogix, and I know it will do the sort of fake SLC addressing where, for example, B3:0.0 becomes B3[0].0. But this would require remapping our tags on SCADA, and if there is a way to keep the original tags after conversion, it would sure be helpful.

Thanks all,

W

 

[PreLC]

Keeping your original tags as a backup just for SCADA sounds easier right now, but long term it's the more painful thing to do: Any SCADA tag would have to be manually searched for, no direct linkage to ladder would be available anywhere.

 

[dmroeder]

Drop down menu: Logic > Map PLC/SLC Messages. Was this what you were remembering?

 

[PreLC]

Drop down menu: Logic > Map PLC/SLC Messages. Was this what you were remembering?

This would only be applicable if there is an active SLC500 in the CIP network right? Or can this also be used to expose SLC500 style tags to OPC/SCADA software?

 

[dmroeder]

Yes, SCADA that only knows SLC addresses can map to tags this way. This is how you would get an older standard PanelView to talk to a CLX, for example

 

[widelto]

"Keeping your original tags as a backup just for SCADA sounds easier right now, but long term it's the more painful thing to do: Any SCADA tag would have to be manually searched for, no direct linkage to ladder would be available anywhere."
If you are a contractor that´s fine, you leave the problems to others.
But IF your are the user, I think is better to convert everything now and avoid future PITA.

 

[cardosocea]

But IF your are the user, I think is better to convert everything now and avoid future PITA.

I've seen end users wanting to keep the variable naming... so there's a top of the line S7-1500 near me running a converted PLC5 program where all the addresses are the PLC5 format.



Absolutely disgusting and I'm so, so happy I left that place.



It's interesting that we all say this here, but out in the field resistance to change is absolutely brutal.

 

[TheWaterboy]

Oh man, I have this one PLC where this was done long ago, I absolutely hate it and remap the stuff properly whenever I have extra time.
The PLC-5 endpoint it was mapped to was replaced with CLX so both CLX have these legacy F8 and N7 tag names (in an array no less) that just drive me mad every time I need to work with them. Don't do it!

 

[I_Automation]

It's interesting that we all say this here, but out in the field resistance to change is absolutely brutal.

My way around that is say I gave it a try but it can't be done that way and they have to upgrade.


For this project I would go through the SCADA and rewrite it. Also a good time to talk to the operators, setup tech and maintenance and find out what this SCADA is missing or doing badly/wrong and fix those issues.



Of course I'm also thinking that maybe the OP has a SCADA system like I had to deal with from a German company that wouldn't answer the phone or an email without a service call charge, and refused to make any changes in their system unless we commissioned a complete new system to incorporate one change. Plus it was programmed in Delphi and they weren't providing the source code for anything.