waterboy

Well thats encouraging... :) Radio is Esteem Model 192C 458 mhz. (Looking at MDS 900 series to get better speeds and be able to program remotely, but gotta fix this issue first, ... then get funding :( ) I would have to look at the pinouts, these have been here for a long time 15 remote sites on radio link. PLC is 5/40E Channel 0 is 19.2k N81 BCC and No handshaking NAK = 3 DF1 ENQ = 3 ACK Timeout = 30 Channel 2 is ethernet used at the location.

Channel 0 is System (Point to Point)

These are "Typed Read" and "Typed Write" MSG blocks. I'm not sure I can monitor the buffers in that level of detail. But I do keep hearing the consistent statement of "One at a time" which is what I suspected, so I have to look into making that happen. I should also add that I find that the remote stations can also send data back to this master station at their discretion so that can only compound the problem for the radios providing the link.

There is an ONS after the compare.

They don't all fire at the same time, each one has a compare at the beginning to fire the rung at the appointed point in the timer, i.e. 2 secs, 4 secs, etc. but many can become enabled at the same time because they take 30 sec to fail. If that could be shortened this would work better, 30 seconds is such a LONG TIME. And I am concerned about that faulty link... I'll see if I can come up with something to sequence through them, allowing maybe 5 seconds for each serial connection to complete. if it doesn't make it by then it can probably wait til next cycle.

I have a sequential program that simply goes down the ladder one rung at a time. each following rung depends on teh one above it. I want to add a tag that tells me which rung is currently true. I can MOV a specified value to a register for each rung but if I add a rung in the middle I have to change the value of all the MOV commands that follow. Is there a variable that I can use that is aware of and can insert the rung number that is currently true into a register? Or do Rung numbers only exist in the IDE?

I really didn't think it was possible but had to ask others who know better. I'm pretty sure this is a logic (or perhaps MSG) race situation between 2 processors and their hardware so disassembling the code probably wouldn't show me anything unexpected. I'll try Mikes random number suggestion, its a start. Thanks to you both for the replies.

I had written in ASM in a previous life, and VB now. I suppose I will always be stuck with the PC conventions.

I have a similar issue with mine in that if RSLinx is running and I then connect the USB end, I have to stop and start RSLinx or it will never browse. My case is a little different and I never went from PLC to PLC (mine are PLC5 anyway) with the laptop running so I cant verify the problem you have with the other end of the cable, but I would sure think its just something we have to live with. Here's hoping I'm wrong...

Using a rung like the attached picture works until the value in N10:7 becomes a Negative number. At that point the rung becomes true again and performs the MUL instruction. I wouldnt think this would work like this. Is this sign issue and what is an alternative?

Thanks for the help guys, This bears a striking similarity to what I've read about programming with Drum Memory ;) In one case the A/I card is set for BCD, not sure why its the only one like that, must have been the original programmers preference. The rest are all 2's complement. The book says use BCD for displays but we dont display directly using anything but mA loops. Yesterday I implemented the ideas here, COP'ing the 8 data registers to a buffer area and using bit 15 "filtering" at 2 problem sites and I can see a difference, but not complete elimination. I initially used that bit on the A/I cards data register and it was firing nearly constantly, proving the point quite clearly. I then set it to look at the buffered register figuring that would stop this completely but it still fires occaisionally. Thats not so good. I set up a timer to copy the data from the A/I registers every 5 seconds and still the occaisional zero gets passed on. Next I am going to use that bit to freeze the value and start a timer (for an alarm in case it gets stuck there) and that should filter it out completely, but the question remains... why is the buffered register seeing these negative values? I have the COP instruction right after the BTR, will putting them at opposite ends make a difference?

Seems that the LES instruction works but the GRT doesnt.

I get what you are saying, esentially the last instruction to modify that register wins. But I really dont think thats whats happening. As soon as the value in the register gets to a positive value it works properly again. Its been working for years, only last week when we emptied that vessel and the probe was exposed (and therefore allowed to generate less than 4mA to the module) did the number in the analog module go below zero. The workround is shown below and works but seems unnecessary.

Thanks for that. I'm using a PLC-5 but I imagine that the idea is the same. It says it stores the number in 2's compliment ("stores" WHAT number??) but doesn't clearly state that it will interpret a negative integer to be "larger" than a smaller positive integer.

I take that value and send to to another memory location if its above a setpoint. The next rung uses a LES to move a zero into N:56 if the value is below that setpoint Thats all I do with it. The twos complement idea has merit, the N:10 address is the analog input module and it is set for twos complement. If the GRT is not taking that MSB into account then thats gotta be the answer, I haven't located the manual for that command yet so I cant read up on it. I did MOV it from the analog module location to an integer address and testing that that location with GRT doesnt exhibit the same symptom. Very interesting . . . the MOV command must convert the 2 complement (invert bits and add 1) into a normal integer where the GRT doesnt. Gotta find those docs...

I installed Factory Talk View Machine edition and didnt install RSLinx enterprise edition because I already run RSLinx Professional . Can I use Professional instead of Enterprise edition? FTVME complains at startup that Enterprise isnt installed, but arent Enterprise and Professional 2 different versions of the same product and wont they interfere with each other if I install Enteprise? I need Professional to work with everything else.

Oh Boy , believe me I am aware how RSLinx acts up when too many SCADA are hammering away at the PLC's. Just went through that and pared down from 7 SCADA to 3 SCADA. Still not happy with the errors but Rockwell has given up answering the support replies. Till this project enters the "tuning phase" I'll let that lie. Now I want to point this new PanelView Plus to one of the 2 RSLinx Gateway servers so it doesn't hammer the PLC's either. Guess I'll have to call up rockwell anyway... Thanks for the help.

Thanks, I will remember that Serial port bit. But the last statement you make is indeed a problem, I have enough machines chatting away with the PLCs so as to cause minor problems, I dont want any more than I have. So to that end, as far as FTVME is concerned, do you believe that it can use Professional so I dont have to install Enterprise? I am just gettign my feet wet with FTVME and it keeps complaining that enterprise is not loaded. The help files say I can use whatever OPC server I want. If thats true, and I have Professional configured, why wont it stop complaining about Enterprise?

Let me start by saying that this is my first Panelview project and I just looked the the manual for the first time. So, if the question is dumb, my apologies. I'm not even yet sure which questions to ask yet but here goes. Our existing PV600's (that I have never touched) all communicate by DH+. I have a new PV1000 with ethernet port. I was under the impression that once I figured out how to address tags in the PV that it would be able to get its data from the PLC using "ethernet" without additional hardware/software/drivers. After a brief read I am no longer sure of that. I see in the manual that there is an eth-1 driver built into the PV. Our SCADA uses OPC through RSLinx to communicate with the PLC's . How does the PV communicate to a PLC over ethernet without having RSLinx on it?

amen to that. thanks for the feedback.

IT is not as separate as you might think. with historical data logging to server farms, cross domain networking and security concerns, IT knowledge is certainly needed on the automation side. IT can certainly get in the way with their overreaching security policies, so its good having the IT background to discover the issue and straighten them out when they get in the way.

This PV+ doesn't run CE. At least it doesn't show any indication that it does, I'm an IT guy and I'm pretty sure I would have noticed that. It looks like an embeddedOS other than windows. I was considering buying the RSTrainer package with Factory Talk Studio View Machine Edition (who names these things!!), anyone have any feedback on whether the RStrainer is worth buying and what it would cost in addition to Studio? Another revelation is that this Panelview device appears to be its own standalone SCADA, not dependent on anything else, with its own database and drivers etc. I was expecting that it would act as a view node to an existing SCADA so I am starting to see the light now.

OK it was dumb, panelview32 wont talk to a Panelview Plus, I need the new version of RSView Studio to do that. Sorry for the dumb question.

Hmmm this is a Plus...

Got it. I havent even established a download yet (host error of some type) but thanks for the help. I will read on. BTW whats the diff between a PV and a PV+ ?