Word of warning....Don't use Wonderware DASABCIP driver v4 for SLC

robertmee

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if you want to keep your sanity....

I was all excited to learn that the newest version of the DASABCIP driver for wonderware finally supports SLC 505 for ethernet. Until I actually tried to use it. I have around 2800 tags on a current install and was dismayed to discover that 20% of my tags weren't updating. After ALOT of investigation, I discovered that it was all tags that were either I or O data files. B, F, N, T and anything else worked fine, but tags linked to the Input and Output image registers did not. I happen to use alot of these as I have maintenance pages that visually mimic EVERY I/O module, RIO device, etc. for troubleshooting purposes.

Anyway, I dug out the pdf for this driver (who ever reads the manual first, right). There it was... Even though this driver supports SLC, it DOES NOT SUPPORT dot words. In otherwords, you cannot access an address such as I:1.24/10 (a Rack on an RIO Scanner module), or I:7.1 (channel 1 of an RTD module in slot 7). Nooooo....That would be too easy. They basically tried to take a PLC5 protocol and mush it together to support SLC. So, what you have to do is access them according to how many words in the rack.

For example, let's say in the main rack you have Slot 1, a 1746-IA16 module. No problem, the addresses supported are I:1/0 to I:1/16. Let's say the next module is a 1746-NR8 (8 channel RTD). You cannot access I:2.0 through I:2.7. Nope, no sirreee. You HAVE to access them as I:2 through I:9 (as they are the next 8 words). How confusing is that???? Hold on, it gets worse. Now your third module is an OW16 (16pt ouput). That's not O:3/0...Nope, it is O:1/0 to O:1/16 because it is the first OUTPUT on the rack. Now, here comes the final kicker. Suppose you leave some space in between your modules and then later add one. Well guess what? All your WW item names now have to be shifted by one word (or 8 words if you add an analog module).

I shake my head at this ****. The WW docs say copy all your I/O to Integer files to avoid some of these issues. No thanks. Because I actually use the ItemName (via the .Reference) in my displays for troubleshooting purposes. So, I'll bite bullet and buy RSLinx classic.

I know most of you (and me) are on CLX platforms now and won't have this issue as the DASABCIP server is great for CLX. But for those of us poor slobs who have customers that insist on SLC, factor in the cost of Linx and don't rely on the DAS server, at least at its current state.
 
This address shifting is exactly like Wago PFC addressing schemes. BUT in the Wago you can "Offset" the modules address when you first map them so when you want to add some modules or change the type with one that uses more Words, then you reduce the Offset.

Can this be done in your situation?
 
ghettofreeryder said:
Recommending RSLinx as an OPC server is the worst idea ever. Go with Matrikon or even better, Kepware. Trust me itll save you alot of headaches

Please expand on this.

Why?
Good vs Bad.

For instance...

RSLinx Gateway permits access for monitoring AND programming. So another OPC server would miss these function. What else should we see in the pain you have stuck to the linx suite?

I am in the middle of some decision to acquire the Gateway version and your comment is of much interrest to me.
 
Last edited:
Pierre said:
Please expand on this.

Why?
Good vs Bad.
Because its slow and unstable. We had applications in useright now, and some that were converted to use Kepware, and the Kepware ones are waaaay more stable. They never "lose" tags, and the end to end time is faster. With RSLinx, the cpu load would be 45%, with Kepware, 2%. Its because of the way RSLinx polls for data. Its also a V2 opc server. Kepware is v3, which has performance boosts, and is also pushing OPC UA, which is a DCOMless OPC( cant f-ing wait)
 
I'll stand behind KEPware. I currently work on a ControlLogix that interfaces through KEPware to a OLD TI. It just always works.
 
The word shifting by slot number for real IO's is nothing new for Wonderware IO drivers. I believe some of their other drivers for SLC will do the same. What really sucks about this is that imagine you remove a slot or add a slot in the middle of the rack. Guess what, the shifting problem manifests itself and all tags for slots to the right of the rack will have to be changed.
 
ghettofreeryder said:
Recommending RSLinx as an OPC server is the worst idea ever. Go with Matrikon or even better, Kepware. Trust me itll save you alot of headaches

Oh, I'm sure there have been worse ideas ;)

I'm not recommending or even endorsing Linx. In my last statement of my original post, I'm saying factor in the cost of Linx or ANY other OPC server that you prefer, but don't rely on the freebie DASABCIP for SLC unless you have a small app and can manage the word shift issues.

Linx is the solution for this facility as they already use it for other applications and are satisfied with its performance. In all honesty, I've done probably 20 or so SLC/WW projects through the years and never had an issue with Linx dropping tags or not working. However, I'll keep in the back of my mind your issues and monitor the situation and have kepware as a backup.
 
Yes, there probably are worse solutions. We had multiple installs of RSView32 and RSLinx, and I think the issue is when both are used in conjunction. I still stand by my previous statement in saying that RSLinx is not a real good option. Kepware is my server of choice, AB driver is only $795. Matrikon is also good, but i dont like the way they layout the data(by datatype, not tag name)
 
rdrast said:
Just as a rule, partly because of dealing with WW and that exact problem over the years, I never ever ever ever ever directly read I/O with an HMI.

I don't think this is just a WW issue. Seems like I have run into this with AB stuff also.
 
Agreed. Using intermediate addesses would eliminate this issue the OP mentioned. Plus, if diagnostic screens, etc are used commonly. Its much easier to create a screen template that uses addresses other than actual IO points. Then you can leave the screen(s) alone and a move or copy instruction takes care of populating the data.
 

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