DirectSOFT 6 for A/B Dummies

This not going to be as easy as I had thought. I have found about 1 in 10 customers in the water industry with any existing wiring diagrams or documented programs. I am going to be spending a lot of hours in "tug test" mode following wires all over the place. . . which is hard to do from 120 miles away. It is not like my other jobs where I could walk back and forth between my work place and my machinery when I ran into missing info. I have been chuggin' along pretty quick with the A/B systems I have encountered, but today....

I am lost in DirectSOFT land, and starting to get a little frustrated. I am trying to get around in a DL06 project using DirectSoft 6. I have uploaded and saved two programs from a customer site. Of course there is no documentation, no electrical diagrams, no nothing.

So, I need to figure out everything from nothing which has been easy for me with Allen Bradey PLCs, but I am having a hard time with DirectSoft.

I did find Bernie Carlton's web page on the subject and found it quite useful in general.

Questions remaining:
1) How do I track down the I/O data points (including an add on analog module) in the PLC memory/data tables? I understand that the discrete points are X and Y, but what about analog add on cards?

2)Where is a list of "special registers" that I can refer to for e DL06? Apparently there are a lot of SP contacts that mean something, but what?

3) PID. I am pretty sure there is a PID block in at least one of these projects, but how do I see it, and can I see it when offline?

4)Data tables. I have found the data view windows, but do I have to fill in the blanks? Is there some easier way to set up my work space so I can quickly jump between a data point in an instruction to a window with a cross reference? Can I see the values stored in those locations when offline?

Thanks for any advice.
Paul

While the analog cards do occupy X and Y I/O points the DL06 system, after initialization of some memory locations (grab the analog manual), automatically processes the data from V registers to analog outputs and from analog inputs to V memory registers.

Special system bit locations are detailed in Appendix D of the DL06 manual. Special system V registers are detailed starting on page 3-29.

Chapter 8 of the manual provides the introduction and methods of controls for PID. The PID loops themselves do not appear as instructions. Go to 'PLC' - 'Setup' - 'PID' for setup and control of the loops.

Yes you will have to set up the Data Views. If you enter one location you can enter those which sequentially follow by clicking CTRL-Enter starting from the first one.

You can use 'Tools' - 'Memory Editor' to observe sections of data tables but they don't update in real time.

If you have 'View' - 'Cross Reference View' open then clicking on an element in the ladder will move the XRef view to that item. Double clicking on a location reference in the XRef view will move the ladder to that point.

Note that we haven't moved to Directsoft 6 (from 5) yet but this should all still apply.

I'll follow this thread and give as much help as I can.

Having done lots of upgrades on water/waste water projects, i feel your pain. Only 1 site had a DL06. many are Allen Bradley. and some are Omron in my neck of the woods. Also an oil company up here has lots of DL06 installed and altho i am not their regular guy, they do occasionally call when he is not available.

As for help, i was going to mention Bernies website cause it has helped me alot as well (Thank you) other than that i think he can help more than i. Good luck with your new position.

Slowly but surely, I am getting there. It is a bit cumbersome, but being the only customer using A/D, I can live with it. Once I get some of the instruction mnemonics memorized, I can speed this up a bit. Since the flowmeter signal I am most concerned with is coming from an orifice DP transmitter with SQRTR involved and a bunch of interim storage locations, there is a bunch of extra math I need to nail down. Having some of my new comments showing up in the ladder view is helpful.

I am finding it a lot more time consuming than RSLogix, but that is why they get the big bucks I suppose. And I am sure if I had started out with A/D I would be nearly as lost in Logix-land. It would sure be nice if the Data View would show the contents of the memory locations for working offline.

Thanks for the help!

EDIT: A couple more:

LDR R100

That loads the accumulator with the 32 bit Real constant 100.0, correct?

Also, in some places the original programmer is putting some real values in addresses in V memory locations that begin with even numbers, but in at least one place he is using an odd number. Assuming he later addresses them at the same starting memory location, this is fine, right?

1. While the Data Views do not show saved values the 'Memory Editor' will show those. Make sure to save the 'Project' to disk, not just the 'Program'

2. Yes, LD R100 loads the REAL (floating point) version of the number into the 32 bits of the accumulator. Remember when saving a Real to use OUTD to send the value to two adjacent registers. In documentation I always make sure to doccument the second of two registers used for a double or real value.

One other point with DirectSoft:
Make sure that when you connect to the PLC that you "Save Project to Disk" and not just "Write Program to Disk".
When you replace a PLC/Processor and only have the "Program" saved to your PC, and not the "Project", then you have lost your PID and any other special configurations.

EDIT: Bernie's got your back

Interestingly, in one case, he used OUT (instead of OUTD) to send the result of some floating point (real) math to a destination. I made a rung comment stating such, but will have to eventually find out where this value might be used in the external world to be sure it is a mistake and not intentional.

I think I saved the whole project correctly since I do have what seem to be valid values in the memory viewer when working offline and I have a pile of files in the folder where they were saved, but thanks for the tips!

And wouldn't ya know, V5002 is the Setpoint of a PID block that is smack in the middle of the control problem the customer is having... hmmm...

I just got an email attachment from the last PLC guy who had to work on this system "blind" like me so I doubt if he spent much time creating comments. Is there any equivalent to the "Compare" utility as found in RSLogix500?

'Tools' - 'Compare Programs'.

You'll get the program differences in mnemonics and location. Not the pretty side-by-side of RSLogix500.

The setpoint for PID is only a single word so that by itself shouldn't be a problem.

I don't think there is any kind of 'PID Compare' ability.

Very good. It would be nice to be able to compare data, but knowing the ladder logic is identical with a few clicks is good enough for now. This system only has one PID so I compared the data in it manually between the older and newer projects and did find differences. I am pretty sure the other PLC guy just tried to tune the loop and did not try to fix all the logic problems. The system itself has design problems but I don't even want to get started on that yet.

I just want to try to figure out why the 4-20mA transmitter reads 0.42 MGD flow at 4mA and how the chlorination valve signal is derived so I can make sure it is doing the best it can with the available signals. Once I have all the relevant stuff commented, on our next visit I can monitor things that actually mean something to me.

The one programmer i talked to years back said he uses exclusively DirectLogic is 1 because of price, but 2 because of less people trained on them, so more likely he will be called back in the future lol.

As for the flow issue, SquareRoot Flow calculations on Orfice Diff pressure measurement have \n inherent issue that may be realavent. when the PV goes between 0 and less than 1, it causes an exponential increase in "Fake" Flow measurement. that is why they usually have a low flow cutoff that would take care of it and force it to zero. also sometimes it is neccesary to change the orfice size to a different size for accuracy.

On a side note. Congrats on 10 years on this forum! Been 3 years for me but i am novice. lol

Good info DwSoft, Thanks!

Okay, today, I was looking for the PID trend I saw when on site. It seems in the copy of the project where I have updated the documentation, I have hidden the PID View tab and cannot get it back. It is still visible when I open the original copy of the project. How do I get that tab or button back? I am talking about the PID trend view.

Also, how does the bias work in DL06 PID? In this system, the chlorine feed command is controlled with a PID loop with the process signal coming from analyzer with significant lag. Apparently, it worked reasonable well when set up originally. Since that time, a variable speed drive has been added so the pump flow rate is now variable, and the flow rate was added to the PID as a bias. This seems wrong to me, based on my understanding of bias in A/B systems.

I would think that the flow rate would be the main driver of how much chlorine is needed and that the results of the chlorine analyzer would be used to adjust the over all rate or scaling of the chlorine to water flow.

And, once I get my PID tab back, learn a bit about online editing, I think I will be ready to make the journey back to the site and see what damage I can undo.

Thanks in advance,
Paul

Okay, today, I was looking for the PID trend I saw when on site. It seems in the copy of the project where I have updated the documentation, I have hidden the PID View tab and cannot get it back. It is still visible when I open the original copy of the project. How do I get that tab or button back? I am talking about the PID trend view.

Click to expand...

I believe it only shows up as an option under the 'View' menu selection while online. Possibly if you save the program and not disconnect from the PLC when you shut down Directsoft it may still be there when you open it offline. I don't see a way to cause it to show up if it isn't there when you are offline.

bernie_carlton said:

I believe it only shows up as an option under the 'View' menu selection while online. Possibly if you save the program and not disconnect from the PLC when you shut down Directsoft it may still be there when you open it offline. I don't see a way to cause it to show up if it isn't there when you are offline.

Click to expand...

Good. So I am not crazy. Right after I posted that, I re-opened the file where I could see it, and it was gone. Apparently, DirectSOFT also does some saving of things whether you like it or not. And it does not seem to have a means to change the default project search path. I should make a list of suggestions for them...

In Directsoft 5 (not sure if this applies to Directsoft 6) from the DSLaunch window go up to DS500.ini (now probably DS600.ini). Open it and scroll down to '[PATHS]'. Edit, save then close and re-open Directsoft. There's lots of other stuff in that file also. Go to here - selet FAQs - select 'DIRECTSOFT - follow the first two mentions on editing the '.ini' file.