GE90-70 Logicmaster 90 application help

surajchem

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Join Date
Apr 2012
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houston
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16
Hi All,

I recently had an opportunity to visit a plant that was running GE90-70 redundant PLCs with Genius RIOs communication to CImiplicity SCADA. I initially thought that the Application was done in PME 7.0 and was able to use the serial cable and upload the project using PME software. The program uploaded with no comments. However, when i went to get the backup of the SCADA program, I saw that the previous engineer made back ups of both the SCADA and PLC. When i looked at the PLC files, It struck me that the PLC application was made in LM90. I had the LM90 master software and was able to open the files using a few youtube videos as a guide. The client has asked me add a few PID loops.

I have a few questions:

1. If the PLC was loaded with LM90, how was i able to upload the program with PME?.

1a. If so, can I make online changes with PME to add the 3 PID loops without going back to LM90

2. If 1a option is not possible, I would have to use LM90 to make the changes. does LM90allow online changes?

LM90: Questions

I have plenty experience with PME, but this would be my first time with LM90. Before going to a site i would like test the process of upload, download in my office. So i have few queries about this software:

1. I am able to get hands on GE 90-70 PLC that was programmed with PME. Will i be able to create new application with few logic in LM90 and download to this PLC and test the whole process of testing my logic and upload/download procedure. And when once i am done, load the PME application back into it. I am not sure if I would have downgrade the firmware of the PLC?

2. , Does LM90 have option to make offline changes and download only changes, if so will it stop the PLC when downloading?.

I would appreciate all the help in this matter
 
Once a program has been modified using PME, it can no longer be opened with LM90. But the PLC itself doesn't care what program you employed to create the program you want to download to it.

In answer to question 1, PME can recognize and upload a LM90 program. LM90, being older software can't recognize a PME program.

In answer to question 1a, you will find that after uploading a LM90 program using PME, you will be in a "Logic not Equal" state. Thus, you won't be able to make online changes without first downloading what you just uploaded.

In answer to question 3, LM90 permits online changes.

In answer to LM90 question 1, yes to both downloading a LM90 program to a PLC previously programmed using PME and to later downloading the PME program to the same PLC. I doubt if the firmware will be an issue, but I can't give you any guarantee.

In answer to LM90 question 2, you can generally download program changes to a 90-70 without stopping it. The way LM90 does online changes, it will download the only the modified program blocks to available free memory and then change the starting address of the subroutines. Doing this enough times eventually creates fragmented memory. If there is not a large enough block of free memory to accommodate the modified program blocks, the online change won't be possible. In that case you would have to stop the program before downloading.

Having said all that, the fact that you have a redundant system complicates things. GE offered multiple redundancy strategies over the years.. Some of them included proprietary program blocks along with the ladder logic specific to the application. Your best bet is to get the manuals for your particular redundancy strategy and familiarize yourself with the procedures for making modifications and for downloading those modifications to both CPUs.
 
I have spent a lot of time with redundant GE processors. The 9070 series still required that you download the program to each processor separately. Are these ethernet processors or serial only? If I recall correctly with ethernet when downloading with proficy the redundancy will not work correctly if the processors have identical target names. I've historically just suffixed the name with an A and a B.
 
Responding to your PM here for others to learn as well.

Thank you for replying to my question. I am using the GE Serial cable to connect to each of the PLC names L2PLC01 and L2PCL02. When i reached the site, I saw that the L2PLC01 was secondary and L2PLC02 was primary. I went online with L2PLC01 using the file LM90\L2PLC01. I saw that there was a mismatch for only one logic block and i went ahead did a load from PLC to PC. Then I went online with L2PLC02 PLC using the LM90\L2PLC02 file. I saw there was mismatch on several logic block. I still went ahead did a load from PLC to PC so that i have the most currect files for both PLCs.

The scope of work is to add just one PID loop to the Logic. So I have the following questions:

1. Which PLC should i go online to make the changes (My guess is the primary PLC)

2. How do i make sure that the secondary PLC has the updated logic. DO i need to go online with secondary PLC and redo the same logic online? or is there a command to synchronise the logic from primary to secondary?


You will have to download the program to both processors separately. Both processors should have a logic equal program aside from the processor names and standby logic. If you have multiple changes from one processor to the other you have an issue.

Also just to point out the 9070 series needs to probably be upgraded to an rx3i.
 
surajchem, have you given any thought to keeping the PID loops synchronized in the two CPUs? If you don't, you run the risk of an upset to the process when you need to switch between the primary and secondary PLC. If there are other PID loops in the program take a look at how they are kept synchronized.

In addition to converting the 90-70, you should also consider replacing the Genius devices.

Emerson's redundancy offering with the Rx3i and Profinet is easy to implement. For several years I was responsible for maintaining a 90-30/Genius redundant system. When we converted to Rx3i/Profinet I was pleasantly surprised by how easy and painless the transition was.
 
surajchem, have you given any thought to keeping the PID loops synchronized in the two CPUs? If you don't, you run the risk of an upset to the process when you need to switch between the primary and secondary PLC. If there are other PID loops in the program take a look at how they are kept synchronized.

In addition to converting the 90-70, you should also consider replacing the Genius devices.

Emerson's redundancy offering with the Rx3i and Profinet is easy to implement. For several years I was responsible for maintaining a 90-30/Genius redundant system. When we converted to Rx3i/Profinet I was pleasantly surprised by how easy and painless the transition was.

I totally agree, the newer profinet redundancy is so simple. Having the redundant IP and making the single download to both processors is almost like magic.
 

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