How does GE PAC compare to AB PAC

[Wulfgar 5]

I'll be doing my first GE project due to customer spec. I'm curious how the Rx3i PAC compares to an AB compact logix as far as programming. For those that have used both how do they compare? Is there anything to watch out for or avoid with hardware or software? This is for a new machine with a customer that is all GE PLCs (90-30/70). Not sure if they have any PACs yet but that is where I'm trying to steer them since the old 90-30 looks to be pretty outdated by todays standards. The project will use GE HMIs as well. I was supprised that they don't have a rackless PAC (unless the VersaMax is but it looked pretty limited) nor do they offer a Rx3i with built in ethernet. Thanks

[RussB 22]

Well, we are even here as I have no experience with the AB PAC. People whom I have talked to compare the programming as very similar, a few differences: In the GE Fanuc world you are not forced to use 'symbolic variables' it is optional or mix them. GE Fanuc has a lot more RAM available, either 10Meg or 64Meg. GE Fanuc allows use of either the 'older' style 90-30 I/O modules or the newer PAC modules. I recommend using only the 'Multipurpose' power supplies. If this involves Motion the new PAC Motion stuff is hard to beat, it insures no more than 1Ms update time for all axis, regardless of how many you add. Timers and counters work differently than in the AB world, learn the difference. User Defined Function Blocks can be a bit tricky but very powerful, learn how to use them. Have fun with it.

[Wulfgar 5]

Thanks for the reply Russ "People whom I have talked to compare the programming as very similar, a few differences: In the GE Fanuc world you are not forced to use 'symbolic variables' it is optional or mix them." Sounds similar to Omron's PLC, (still waiting for Omron to come out with a PAC). "GE Fanuc has a lot more RAM available, either 10Meg or 64Meg. GE Fanuc allows use of either the 'older' style 90-30 I/O modules or the newer PAC modules." AB doesn't make anything backwards compatible. GE seems to have more in common with Omron on this. "I recommend using only the 'Multipurpose' power supplies." Ok, any specific reason? "If this involves Motion the new PAC Motion stuff is hard to beat, it insures no more than 1Ms update time for all axis, regardless of how many you add." It's very likely I'll have some servos, I'll have to look into the GE motion options some more. I see they have rack mounted and standalone servo controllers. "Timers and counters work differently than in the AB world, learn the difference." I don't think that will be a problem. "User Defined Function Blocks can be a bit tricky but very powerful, learn how to use them." I agree, I used them for the first time on my last Omron project, definatly very handy. Omron has a decent library of function blocks, especially for motion. Thanks

[RussB 22]

"I recommend using only the 'Multipurpose' power supplies." Ok, any specific reason? Just in case you need to add one later. If you have a "standard" power supply you would need to replace it first. "If this involves Motion the new PAC Motion stuff is hard to beat, it insures no more than 1Ms update time for all axis, regardless of how many you add." It's very likely I'll have some servos, I'll have to look into the GE motion options some more. I see they have rack mounted and standalone servo controllers. The PAC Motion is the Rack mounted using the GE Fanuc red-end-cap digital servo motors and fiber optic communications. "User Defined Function Blocks can be a bit tricky but very powerful, learn how to use them." I agree, I used them for the first time on my last Omron project, definatly very handy. Omron has a decent library of function blocks, especially for motion. GE Fanuc has an excellent set of standard function blocks also, but the custom UDFB are a bit hard to find on the web. Be sure to start at the 'support' area in NA it is www.gefanuc.com/support Good luck, have fun with it and use the forum as a source of information that you can not quickly locate. R~

[BITS N BYTES 66]

Neither GE or AB can match the power of the IndraControl series PACS from Rexroth. Admittedly the IEC61131-3 compliant CoDeSys programming takes some getting used to, but once mastered it's a joy to use. If you need the added complexity of motion this is easily implemented and tightly integrated into the Indraworks control suite. I completed a 24 Axis project last year and will NEVER go back to AB. Check it out. http://www.boschrexroth-us.com/business_un...er_en/index.jsp

[Joern 0]

Probably the Bosch controller is good for general PLC functions, but the new PACMotion servo controller is a rocket: CAM execution with polynom 5th degree. At the other side, can Bosch Rexroth beat the MTBF of Fanuc motors? I'm sure - NOT! The Fanuc encoders work with 64k to 1M pulses per revolution - that is the argument for accuracy.

[Wulfgar 5]

Thanks RussB, I'll hunt down those function blocks for PACMotion once I get the software. BITS N BYTES, I would like to try a Rexroth PAC, from what I've read they sound pretty cool. But for this customer they want GE for all control and HMI. We do some PC based systems but they are always done by our VB.Net guru. If I had a choice I would only use open protocols and not use AB at all. We try to steer our AB customers away from using AB HMIs but some customers are pretty stuburn. Joern, What about using Rexroth with Fanuc servos? I'm assuming you could use pretty much whatever servo motor you wanted that supports standard interface. Thanks for the responses Edited 21 Nov 2008 by Wulfgar

[Peter Nachtwey 15]

Pulses per revolution isn't the limit. It is the pulses per second. Does the BRR control exceed 12 million counts per second. If so they are finally catching up.

[Joern 0]

Fanuc motors use a proprietory protocol for encoders. You can use the Fanuc motors only with Fanuc CNCs and GE Fanuc PLCs (DSM314, DSM324, PACMotion PMM335) Joern

[Wulfgar 5]

I recieved the Proficy Machine Edition 5.90 earlier this week. After spending a couple of days with the ladder editor my first impression is that their software needs a lot of work to get it up to par with the compitition. The interface seems very outdated and I've ran into quite a few bugs or odd quirks so far. I'm waiting for a response from GE on about 15 questions so far. It seems to be very outdated like it was developed in DOS and ported to windows instead of being made for windows. It doesn't even auto format rungs so the rungs end up looking really ugly if you don't make them exactly right to begin with. I've not messed with the View yet hopefully it is better than the ladder otherwise this is really going to be a long painful project. Any tips or tricks to write ladder quickly in Proficy? I found a list of shortcut keys but they do not include basic things like NO, NC contacts and output couls. Is there a way to write the code in excel and import like AB or Omron? I tried to copy a rung and paste in excel but it was quite ugly and had way more stuff in it than just the ladder code. Edited 2 Jan 2009 by Wulfgar

[Steincollector 0]

Bosch Rexroth is able to do 5th and 7th order polynomial cams in the drive. BR Encoders are accurate to +/- 20 arc seconds and 16 million bits/rev(counts/rev) of the encoder of data. Every 250 microseconds we close the position loop in the drive, so I would say we can do 12 million counts per second.