You are not registered yet. Please click here to register!


 
 
plc storereviewsdownloads
This board is for PLC Related Q&A ONLY. Please DON'T use it for advertising, etc.
 
Try our online PLC Simulator- FREE.  Click here now to try it.

---------->>>>>Get FREE PLC Programming Tips

New Here? Please read this important info!!!


Go Back   PLCS.net - Interactive Q & A > PLCS.net - Interactive Q & A > LIVE PLC Questions And Answers

PLC training tools sale

Reply
 
Thread Tools Display Modes
Old November 15th, 2018, 11:16 AM   #1
EngMan813
Member
United States

EngMan813 is offline
 
Join Date: Oct 2018
Location: Florida
Posts: 11
RSLinx Classic OEM thinks PLC is still on when it's turned off

Hello,

I'm a novice PLC user but advanced Excel VBA user. I've created a program to capture and email data from our PLC. The capture happens once an hour as it reads the tags in the PLC. Our second shift ends at 3:30AM on Saturday mornings and RSLinx isn't detecting when they shut the machines off for the weekend. It also doesn't detect when the PLC is turned back on for the morning shift start on Monday.

I read that there may be an issue with RSLinx where it loses it's "mind" or stops "auto-Browsing" if it doesn't detect a PLC for a period of time.

Is there a way to keep this auto browse alive even when PLC's are powered off? Like is there a "timeout" setting that can be changed in RSLinx to maintain the autobrowse longer?

I have VBA to look for tags to see if the PLC is online, but I have to uncheck and then recheck the "Autobrowse" checkbox to get RSLinx to see the state change in the PLC after the weekend.

It seems to be an issue for both PLC shutdown and startup.

I appreciate all your thoughts and responses.
  Reply With Quote
Old November 15th, 2018, 12:39 PM   #2
rdrast
Lifetime Supporting Member
United States

rdrast is offline
 
rdrast's Avatar
 
Join Date: Apr 2003
Location: South Carolina Lowcountry
Posts: 5,307
Are you using a licensed RSLinx as an OPC Server? With named topics? The browser shouldn't matter there.
Sorry, I don't remember if RSLinx provides a connection status tag or not.
__________________
------------------------------------
How to ask questions the SMART Way!

Look First, Ask Second!

  Reply With Quote
Old November 15th, 2018, 12:48 PM   #3
EngMan813
Member
United States

EngMan813 is offline
 
Join Date: Oct 2018
Location: Florida
Posts: 11
Yes, licensed version and utilizing DDE with named topics. RSLinx just seems to give up if it doesn't see the PLC after long periods of time (hours perhaps??).
  Reply With Quote
Old November 15th, 2018, 03:21 PM   #4
thingstodo
Member
Canada

thingstodo is offline
 
Join Date: Feb 2012
Location: Saskatoon
Posts: 247
Quote:
Originally Posted by EngMan813 View Post
Yes, licensed version and utilizing DDE with named topics. RSLinx just seems to give up if it doesn't see the PLC after long periods of time (hours perhaps??).
DDE has .... is the politically correct term 'issues'? ... determining communication status. It has a bunch of .. timers, timeouts .. not sure what to call them ... embedded inside the network layer. You don't have access to see them or to change them. Microsoft stopped talking about DDE support around 2004, when they started pushing OPC and DCOM.

If you are running a licensed RSLinx Gateway, you can make your VBA code a whole lot more complex, but *MUCH* more reliable, by using the support for OPC 2.0.

DDE is sort of like a message sent out by the source, with no feedback to the source on whether the message was received, or by how many receivers.

OPC 2.0 is more like open a named channel, set up a request for a list of tags, read the tags, and close the channel. You, as the guy that is receiving the data, know whether the channel is open, you get a fail code if it does not work, you can retry, you now how much data was received, etc. I've lost the technical details - I have not made one work except in a lab demo.

OPC 2.0 also has the option of building the list of tags, then requesting an update rate, and keeping the channel open .. or maybe you have one channel for the setup and one for the data being received ... I can't remember. It's more setup, but it is good for getting repetitive data and storing history.

Since you are requesting data once a day or so, I'd just to the open-request, receive, close method. And if the PLC is not accessible when your code is run, you WILL get an error message. And you can exit your code properly.

Sorry - I don't have example code. Rockwell is pushing the OPC 2.0 thing so your sales person or one of the technical guys should be able to dig out an example and send it to you.
  Reply With Quote
Old November 15th, 2018, 03:44 PM   #5
EngMan813
Member
United States

EngMan813 is offline
 
Join Date: Oct 2018
Location: Florida
Posts: 11
Thanks thingstodo -

I've read several places where DDE isn't as reliable as OPC. I was, unfortunately, given the task of creating the Excel method (collect hourly, email daily results) with very little PLC knowledge. One of the other engineers here told me about DDE and gave me an example. I just ran with it.

I'm open to reprogramming with the OPC method, but I just would have no idea where to begin (i.e. what do I need to run on the PLC computer to get the communications - RSLinx?, what is the collections scheme....)

Not knowing if this will even fix the issue is the other side of the coin.

A bit more info that might spark additional thought:

My setup is this:

Laptop with RSLinx and Excel ---> Ethernet ---> PLC

The only time that I get issues is when the users shut off the PLC (connected to the UPS that they power down at end of 2nd shift on Saturday mornings. RSLinx doesn't detect that it's off and doesn't show the red X's. If I uncheck and recheck the "Autobrowse" checkbox, it refreshes and detects that the PLC is off. Its the same for power up on Monday mornings.

I'm looking for an open channel to the PLC, a hotlink to the "SurgeOK" as well as a "MachState" to see if it's online, and they are all "1's" until I uncheck and recheck the "autobrowse" then they go to the expected #N/A or #REF! state that I use to stop looking for data. Same at power up - they don't change until I physically uncheck and recheck the autobrowse box, then all is good.
  Reply With Quote
Old November 16th, 2018, 02:03 AM   #6
AustralIan
Member
United Kingdom

AustralIan is offline
 
Join Date: Jan 2013
Location: UK
Posts: 790
My initial thoughts are that using Excel as a UI is not the way things are done. Probably for the reasons you mentioned. Use SCADA, or even a HMI.

Your VBA experience tells me you will be comfortable with AdvancedHMI. You could even get it to spit out an Excel file whenever you want, or make MUCH better user interfaces.

Cheaper than rslinx OEM too.
  Reply With Quote
Old November 16th, 2018, 07:37 AM   #7
roxusa
Lifetime Supporting Member
United States

roxusa is offline
 
Join Date: Nov 2008
Location: NJ
Posts: 663
I use excel with with Linx Classic Gateway and the OPC server set to read a Micrologix 1400, I have the Micrologix 1400 reading messages from all my machines for the Data needed. I have it running constantly for years and is great. I use the ER bit for the first message to any of the other PLC's to latch a bit that stops the other messages for that PLC and the DN bit to unlatch it this notifies me that machine is off line.
I know how to bring data into the Excel for some of the use but have an another guy good with excel that wrote most of mine and it will email me different conditions.
__________________
B.Pedersen
if you are going to assume, assume your wrong.
  Reply With Quote
Old November 16th, 2018, 08:00 AM   #8
EngMan813
Member
United States

EngMan813 is offline
 
Join Date: Oct 2018
Location: Florida
Posts: 11
Thanks AustraiIan -

Unfortunately, I was given RSLinx and asked to make it work. I'm close, I just can't seen to get it to know when the PLC has been turned off for a long period of time (weekend) and then turned back on. It just sticks with the last state even when "Autobrowse" is still checked.
  Reply With Quote
Old November 16th, 2018, 08:01 AM   #9
EngMan813
Member
United States

EngMan813 is offline
 
Join Date: Oct 2018
Location: Florida
Posts: 11
@roxusa -

Any chance you might be willing to share your setup and sample Excel file? Obviously with any sensitive data removed.
  Reply With Quote
Old November 16th, 2018, 08:30 AM   #10
roxusa
Lifetime Supporting Member
United States

roxusa is offline
 
Join Date: Nov 2008
Location: NJ
Posts: 663
what RSLinx are you using. In linx I create a topic and point it at my 1400
In RSLinx go to Edit It will drop down Copy DDE/OPC Link
Click that a box opens,expand left column& scroll down left side column and find your topic you created expand it and go to online,expand and find the data looking for in the PLC such as n7 double click it it will open on the right column
find the integer (example) N7:5, double click and say OK to close box.
Open Excel and right click a box and do Paste special, box opens keep unicode but check paste link, The live info from N7:5 is now running on that spread sheet
Try that and let me know
__________________
B.Pedersen
if you are going to assume, assume your wrong.
  Reply With Quote
Old November 16th, 2018, 08:32 AM   #11
roxusa
Lifetime Supporting Member
United States

roxusa is offline
 
Join Date: Nov 2008
Location: NJ
Posts: 663
I create an Excel page to list all data I need to collect, Have to do One at a time but when done my guy uses data to make fancy bars and Graphs and formulas to display
__________________
B.Pedersen
if you are going to assume, assume your wrong.
  Reply With Quote
Old November 16th, 2018, 08:38 AM   #12
BruceJW
Member
South Africa

BruceJW is offline
 
Join Date: Jan 2006
Location: Randburg
Posts: 55
Hi, I am not an expert with Factorytalk Vantagepoint, but with it you could probably achieve a much more reliable solution. If only one small spreadsheet it might not be worth the cost.
  Reply With Quote
Old November 16th, 2018, 08:46 AM   #13
EngMan813
Member
United States

EngMan813 is offline
 
Join Date: Oct 2018
Location: Florida
Posts: 11
@roxusa -

I have no problem with creating hot links or gathering the data every hour with my VBA, the issue comes when they shut down the PLC's on the weekend. RSLinx stays running on the laptop that's connected to the machine via ethernet and it just hangs like it's still connected (no red X's). Since I use VBA in Excel to look at the @IsPresent hot link on my spreadsheet it thinks its still connected, but eventually exits the routine since the PLC is actually off.

It's the toggling of the hot link bit from the PLC through RSLinx. RSLinx just seems to not know how to handle when PLC's are shut off.

The spreadsheet and VBA I created works great all week when they leave things on, it's just detection of the off state of the PLC and then it returning to the on state.
  Reply With Quote
Old November 16th, 2018, 09:12 AM   #14
roxusa
Lifetime Supporting Member
United States

roxusa is offline
 
Join Date: Nov 2008
Location: NJ
Posts: 663
Maybe I'm not experiencing that because the 1400 I collect from never gets turned of unless power failure. The production PLS's get turned off and my 1400 simply cant see them. I have RSLinx on auto brows and it never stops. I will test this weekend what happens if all PLC's on Linx are off a while.
__________________
B.Pedersen
if you are going to assume, assume your wrong.
  Reply With Quote
Old November 16th, 2018, 09:36 AM   #15
BruceJW
Member
South Africa

BruceJW is offline
 
Join Date: Jan 2006
Location: Randburg
Posts: 55
Hi, what version of RSLinx are you using?

edit: https://rockwellautomation.custhelp....il/a_id/929723
  Reply With Quote
Reply
Jump to Live PLC Question and Answer Forum

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Topics
Thread Thread Starter Forum Replies Last Post
Can RSLINX Classic Lite communicate with a real PLC (SLC0) IdealDan LIVE PLC Questions And Answers 9 February 9th, 2018 02:09 PM
RSLinx Enterprise not finding a PLC that Classic Can Neven87 LIVE PLC Questions And Answers 4 July 29th, 2017 04:08 AM
PLC Update - Back Issues Collection Now Available! Phil Melore LIVE PLC Questions And Answers 11 October 22nd, 2015 03:17 AM
Cannot Browse Past ENBT RSLinx Classic whussain6 LIVE PLC Questions And Answers 1 August 17th, 2015 07:01 AM


All times are GMT -5. The time now is 09:10 PM.


.