Changing over to Allen Bradely PLCs

[Maintenance Man]

I agree with not replacing something unless it’s broke. The reason we are changing over to Allen Bradley PLCs is because the GE 90 micro logix we have are obsolete. We would have to replace them with newer PLCs from GE. The new PLCs do not work with the hand held programmer the previous owner was using. To purchase the software from GE to program the PLCs is around $1000. We only have 9 machines that will be changed over. Some of the machines are needing rebuilt in which the company who does our rebuilding uses Allen Bradley. We have a large plant that has about 30 machines that all run on Allen Bradley. We also have plants across the country that all use Allen Bradley PLCs. It’s a corporate decision to not spend $1000 on software for one plant when we can use Allen Bradley. I thank you all for responding. For all of you who work for large companies, you know that corporate decision = etched in stone. Well at least the company I work for it’s that way.

 

[Steve Bailey]

Somebody is feeding you incomplete information. Proficy Machine Edition software to program the VersaMax Micro PLCs does not cost $1000. For that kind of money you can get Machine Edition Standard which can program the Series 90-30 GE Fanuc PLCs as well as the Micro PLCs.

Proficy Machine Edition for the Micro PLCs costs around $100 and it can program the Series 90 Micro PLCs. So, for less than the cost of replacing one working PLC, you can purchase the software to maintain it until it breaks.

 

[rsdoran]

My point earlier is you do not need the software if the machine works and is not being upgraded, just have a plan to replace if/when it fails. If you do not have written copies of the program then it will cost in some fashion to do the conversion.

I did not realize that GE had a $100 version for micro's either.

Tell ya what, when you remove them PM em and I will send you my mailing address, I can find something to use them for.

 

[kamenges]

The dissenting opinion

I hope that everyone that is suggesting that Maintenance Man puts off the change is looking at this as an application specific case. You would need to infer that since it is 'only' a micro PLC that the application must be very simple and that a change to a different plc would be a no-brainer. You would need to further infer that, since it is such a simple application, that it must not be production critical.

I like to have my destiny firmly in my own hands to the greatest degree practical. If I know I am running with obsolete devices in a machine I have some decisions to make. Is the machine critical to production and will downtime be very painful? If the answer is no then you can wait and take care of this when it breaks and just eat the downtime. If the answer is yes, wouldn't it be in your best interest to replace this device when YOU determine it is a good time from a production standpoint? I suspect that 9PM on Christmas Eve is not a good time. Neither is when your plant is running at 110% capacity trying to fulfill orders. According to Murphy's Law, that is when the component will fail. If you don't have a spare on the shelf you will be in a world of hurt.

While you can argue the migration path, I find it hard to argue that controlled migration is not the right choice.

Keith

 

[David Roy]

I agree that the GE's are an excellent product and your return on investment will not be there except only to standardize.

 

[Maintenance Man]

Thank you for the reply kamenges. It is a simple program that I have already changed over to Allen Bradley. I just had to change the program a little. The change was done on a weekend. We are going to spend around $600,000. on new packing equipment so we can run more product faster because of a large increase in orders. I had to have a back up plan before we go on line with new equipment. If the old PLC would have gone bad, I would not of had a quick replacment. Thank you all for your advice.

 

[PeterW]

I understand where your coming from now as I have had to replace obsolete equipment in the past.

Not sure if I would replace the lot though, depends how old the equipment is and how much life you expect before it itself is replaced.

Perhaps, if the life is not expected to exceed another 10 years, I may replace 3 units and use those as spare, perhaps using one as a hot spare to ensure it works and only if you get to 1 spare left, replace another.

 

[kamenges]

I like PeterW's idea. That gives you very good protection at a reasonable cost.


Keith

 

[Maintenance Man]

This is good advice for saving some money, but in a few months we are going to be running fast with little room for error. I could use the PLC removed from machine to be used as a spare then upgrade on a weekend when the spare is installed. It will be around $600.00 to upgrade which would more then pay for itself if down time is prevented, which would cost us in the thousands for having workers standing around and lost product and maybe lost customers if they do not get there product in time. Thank you all for very good advice, I appreciate it.