Caught in the middle
I am not sure I am qualified to do what is being asked of me but I am giving it my best shot.
Because of the issues and problems this machine has had since I became employed at this company when/if the upgrade is done I wont have time with learning anything new so I think the best bet is stick with SLC, if possible.
The system has 10 ABB 40 I/O brick style plcs(
Proconti CS31 , Master, Slave and 1 for each deck. There are approximately 30(I havent counted exactly) Remote I/O (12 binary or 8 analog), which means at least 300 remote I/O. There is also 8 communications plc's beside the deck units to communicate with the Bergher Lahr stepper drives, 6 motors per deck with rack mount control unit that communicates via ASCII (I think). The plc's are using a network called ArcNet. The main drive is a Eurotherm 620 Vector Drive (
http://www.eurotherm.ie/drives/guideac.htm
which I am not sure how it communicates or if it does (more I have to know), their are 5 more DC drives(Eurotherm 590), chill roll, rewind(x2), and unwind(x2) that do communicate with each other, the chill roll provides the speed reference for the unwind and rewind but an encoder is on the drum/main drive to provide a reference (again I think).
The CNC/HMI computer is using Wonderware (with some form of a C program) to provide setpoints and parameters for the automation part of the decks action..registartion, print position etc. The Eurotherm and ABB software runs in the background of windows to be used with the HMI. This is a big area where I get lost, that and the fact that I can not monitor I/O in any fashion except lights on the units or remote units. The stepper motor encoders are positioned in a way I can not connect a scope to watch them so it would be nice if I could monitor them in some way via the plc or drive system (another thing I will have to find out).
Here are my thoughts, this system was designed to be fully automated. This doesnt work at this plant ( I know it should), thats another issue that I have no control over nor is likely to change.
I was thinking of using an SLC5/04 Master system in the deck cabinet that would work with the deck drive systems, a large portion (maybe 20 units) are located in the Main/drive cabinet. I was looking at using maybe Flex I/O, possibly on DeviceNet (I am kind of familiar with this), with more remote I/O blocks at the other remote locations and the control console. Or would it be more prudent to use a PLC system in each cabinet and just a few remote I/O? Would there be a cost factor that make using remote I/O a better solution? I was looking at using the plc in the main/drive cabinet for communications with the drives (maybe this would allow faster processing? As it is now everything is terribly slow to respond after initiating an action). The deck unit has 2 handheld manual controllers that allows manual control of the deck movements (the operators use this now to actually set the print instead of using the automatic positioning). I think this would be prefered overall because of past issues. I was hoping to use a Panelview to turn on/off decks when not needed. To replace plates one side of the plate holder has to move away with rest at home, as it is now if any deck isnt HOME then it wont extract/move away properly, for that matter if not at HOME nothing will work. I was hoping to eliminate this issue, if a deck failed to work it could be removed from the sequence regardless of position. Also use the Panelview to create Home position and print off position set points, so it could be taken almost to print or back home in an automatic process. I would also like to monitor things like encoder and I/O via the Panelview. Naturally have alarms. Would it be more prudent to stay with a HMI/SCADA software package like Wonderware or Fix DMACS for process/variable settings? The way the machine is now it uses the same settings all the time, the operators just choose what decks they want to use. Its partially a personal preference but I would like to do away with the computer and HMI software, I may find its needed but at this point I dont.
I know I tend to ramble on. Does any of this sound viable, like I am at least looking in the right direction? I had AB, local distributor and an integrator in today to look at it. The integrator was pushing Controllogix but I cant afford the learning curve time that may be needed once its back online, I may change my mind on this before its over with though.
Alot of this tells me the areas I need to study more and organizes some of this in my head (and on paper).
Any thoughts or opinions on this will be highly appreciated.