CHRI$TOPHER

PLC5 and the new guy

6 posts in this topic

I'm an apprentice electrician who got an associates degree in automation & industrial electric studies. I've been assigned to process control to learn our PLC systems and how to tweak and resolve issues. The fun part is 90% of our PLCs are PLC5 with a scant few RS500 & RS5000 systems in place. Being the plant is 40 years old it's time to migrate to RS5000 but we've already encountered some of the trip ups that occur in migrating the code from 5 to 5000. I've encountered the main difference in finding bits. For example I've been writing code in 5 to get a hang of the TOF bits and using .ACC, EN and DN bits. I had a call the other day to help force a bit on in our newly migrated 5000 program and learned there are no data tables like I've learned on but instead tags for the program. I understand the drilling down to the word level to the specific bit but find that's a very tedious process to change a bit's status.

I learned to program in school on Siemens S7 and the 5, 500 and 5000 programs, while similar are another ball of wax completely. My concern moving forward is twofold- am I wasting my time learning PLC5 and how to troubleshoot it when everything is moving to 5000 and should I spend more time learning the 5000 idiosyncrasies so I have that skill set for future jobs? I feel like I'm becoming proficient in a useless medium and lagging behind the curve of what is being used in industry today. 

 

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Being proficient in the PLC-5 is not going to hold you back at all, especially if you also learn the 5000 at the same time. Going forward, if you had to pick one or the other, I'd say invest more time learning the 5000 than the 5.

I started with RS500 and S7-300/400 PLCs. When I started this job, I had to learn the PLC-5 (no problem for the most part since I already knew the 500s) and Logix 5000. The Logix 5000 processors were a steeper learning curve than the PLC-5s for me, but I've mostly gotten there. I've done a few PLC-5 to Logix 5000 migrations (one was really big...) and learned more about their differences. That migration is easier than a PLC-2 to PLC-5 migration since the software at least is copy-paste compatible.

I do miss some things when I'm working in the 5000 world, like the CDM and data tables, but I've mostly come to terms with it.

One thing I would say is this: be very careful toggling bits in the data tables, unless you are REALLY SURE what you're doing! It would be very easy to grab the wrong bit and toggle it or to toggle the "same bit that always fixes it" only to find that "it" is different this time. I would say it's always better to go to the code itself to verify what's really happening before toggling stuff. Then you can be sure you're working with the right bit and that it's the same problem.

Once you get it going, you can find a way to not have to manually toggle bits with a laptop at all.

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When you say plant, what kind of plant? If it's gas processing or oil terminal I can send you some things that might be helpful.

If it's making beer the best I can do is ask for free samples :-2 

Robotics, etc... I'm out (but interested).

Like Joe E. The bulk of my time was on SLC 500, S7-300/400, S5, and then I moved Logix 5000.The first PLC was Direct Logic and TI505. I've also built out a couple of Delta V DCS projects. My preference is the Logix 5000, by orders of magnitude

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I'm at an aluminum smelting plant. We are 40 plus years old and most of the technology is, too. I'm learning 5000 but I don't have access to the emulator software yet and am getting very little time on the program other than occasional troubleshooting. I am starting to grasp the differences between the 5/500 and 5000 programs but know it'll be a bit before I'm proficient with 5000. Thanks for the insight gentlemen. 

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If you have a spare 5000 PLC (you do, don't you?), set it up on your desk or workbench and "play" with it. Try porting over a PLC-5 program. One of the things I really like about the 5000 platform is that you can inhibit all of the I/O and the PLC will sit there happily running the program without any issues. You can then add an extra program to simulate the I/O. For instance, I've written code in the simulation program that will turn on an input a certain time after its associated output turns on. That way, I can test and validate the logic. You can also adjust the response time of the devices to see how a cylinder that's wearing out would affect the overall machine's operation and find a good way to interlock it with other components and develop alarm messages to notify the operator.

If you don't have a spare PLC, you should definitely get one. At least one. With all of the parts and pieces it needs to operate on your bench (chassis, power supply, network module, etc.).

 

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Joe-

I'll ask my mentor if he has one I can use. I'm currently set up with a 1785-LT-2 PLC5/25 processor and a T/C card, two analog I cards and an I/O simulator module. It has been good experience to write programs for this unit however I am eager to dive into 5000. We have one PLC guy for our whole plant. I'm evidently the only apprentice that has been through this shop the past three years. Not sure if he has a spare 5000 but I'll find out. 

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