I'm new to the whole automation thing. What is the ideal application for these systems?
1) Reliance/AutoMAX
2) PLC-5
3) ControlLogix

This is my understanding of it. ControlLogix and PLC-5 can do pretty much the same thing for monitoring I/O and turning on I/O. But ControlLogix has the additional ability to do motion control, where as PLC-5 doesn't. In PLC-5 systems, motion control is done using SLC?

I really can't concisely describe what AutoMAX does. Reliance makes AutoMAX right? It seems like an "AutoMAX rack" has a processor, I/O, and communication cards. But... what does that do for you? It can do stuff like... hold system wide variables?

 

I think automax is sold as more of a dcs type system.

Both the SLC and PLC5 have I/O cards for motion control, neither are especially good, but for simple things are OK (although I am not sure the PLC5 motion cards are even sold anymore). Best bet if you need motion control is go with a seperate drive/controller package like the ultra drive from AB and use a communications interface to communicate with it. if its simple enough the I/O interface is adequate.

If you chocis is between PLC5 and Clx, go with Clx. It will likely be around long after the PLC5 enters its dotage, and it supports just about anything the PLC5 could do and much more.

 

These are not easy questions to answer since you are really asking which is 'best'. In controls, the inevitable answer to such a question is 'it depends'.

It sounds like you are attempting to factor into the decision some functionality (motion control) that is not required by your application. Best practice is to define your application in terms of required functionality (including any data acquisition) and then select the most cost effective solution. Newer systems are generally lower cost, higher density and more powerful (Moore's law) - for a primarily discrete application, this would argue for Control Logix or one of its competitors. This needs to be balanced against training costs, spare parts inventories and communications to legacy systems -often this argues for staying with whatever you already have.

Whether the decision is between control platforms or flow meters, your task is to develop a requirements definition that can serve as a tool for evaluating the several candidates and then make a recommendation that reflects the balance of functionality and cost. If you intend to do your task well, there is no shortcut.

 

No, PLC-5, SLC-5/00. and ControlLogix all have the capability to do motion, and to do so very well. All three require a motion controller in addition to the PLC processor. The difference is that the instruction set for the ControlLogix has been extended with a number of motion-specific instructions (which turn out in practice not to be as much of an advantage over the PLC/SLC generic-instruction method as you would expect).

The most fundamental difference is that the ControlLogix is designed on more of an object oriented paradigm, which makes some types of applications simpler to write and maintain. It support user defined data types (but not associated functions), for example. A PC programmer would probably be more comfortable trying to learn ControlLogix than PLC or SLC. Also, the Control Logix has field expandable memory and is very very fast.

I've never had any experience with a Reliance Automax and can't tell you anything about them.

 

Wow, you guys know a lot, but it's really a little too much info for me. I'm just wondering, in general, what is "Reliance/AutoMAX".

Like PLC is used for logic (turning on/off stuff). And controlLogix is good for logix AND motion.

So how does Reliance fit into automation?

Thanks!

Eric

 

Answer:
Reliance-Automax, PLC 5, SLC's & Control Logix are all products made by Rockwell Automation.
PLC 5's, SLC's and Control Logix are manufactured under the Allen-Bradley Brand, while Automax is made under the Reliance brand.
In general, all the above product has similar basic components: a processor, Input/output cards, chassi, power supply unit, and a communication interface unit.

Functionality, in general, all four does I/O control. However, there are applications where these PLC's are used only as data concentrators. Meaning no output control, but just data gathering and broadcasting to a server.

Cost is a big difference among the 4.
For example, if you have and application where you have to control 32 discrete inputs, 32 discrete outputs, 8 analog inputs, 8 analog outputs, enet communication, and a total 250 ladder rungs:
The least cost is SLC's,
next will be PLC 5's, Control logix, then Automax.

Note: Micro Logix belongs to the SLC family.

The programming software for each one of the above are different.

Other I/O speciality card are made by third party vendors. Allen-Bradley makes motion-axis controllers for the SLC flatforms but so as others which will plug-in into the SLC chassi.

 

Here's the straight dope on Automax.

Automax (or varations) has been around for years. It started out as AutoMate. There have been Automate 31, 32 and 35 (maybe even a few more.) The Automate line transformed into the DCS 5000, which eventually morphed into Automax. This is a DCS, Distributed Control System. With in the Automax processor you can run a ladder logic program just like in a plc. But, you can also run BASIC and control block programs. If you are a good programmer the Automax system can be extremely powerful. We use them in the paper mill to control whole systems on a supercalendar - three DC drives with tension and current loops and gobs of I/O.

What happened to Automax? You ask. The current from of Automax came about in the 80's. It went through the typical revisions in hardware and software that all product lines go through. But then Rockwell Automation bought out Reliance Electric. Rockwell was working on a line to compete with Automax, because a PLC5 just can't do the drive control like an Automax can. When Rockwell took over Reliance they moved all of the automax technology over to Allen Bradley and created ControLogix. ControLogix, which is more powerful than a PLC5, has all of the programming features of Automax (BASIC, Block, and Ladder). Rockwell has since moved Automax into its "Custom Classic" listing. That means that they only plan to support it for at least 10 more years.

If you are making a choice about which system to go with think twice about the Automax. If you like RA products, you can probobly count on ControLogix to be around for a while.

 

I think everybody else covered the PLC5/SLC/ControlLogix pretty good. Automax is mainly used on paper machines to control the speed of different sections of the machines. It is the brains for AC or DC drive systems. It acts as the supervisor/coordinator for multiple drives tied together to create a control system. The Automax system actually has specialized cards that can be inserted in racks to control power boxes (SCRs) to control the speeds (Armature/Field) of DC motors. (This is actually the older technology) The newer generations of Automax systems communicate to specialized devices via fiber optics to control the Armature/Field on DC motors and also IGBT boxes for AC motors. Automax is a mature product and Rockwell are no longer promoting it.

PLC/5 is only configured via ladder logic but can do motion control. SLC can also do motion control but the newer ControlLogix would be the recommendation if you want to do motion control.

As far as the difference between the PLC5 and SLC, the can do both pretty we the same thing, but PLC/5 can control more I/O and faster. SLC were used alot by system integrators, because of their lower cost. One inconvenience with the SLC is that programming cannot be done on the run, but possible with the PLC/5

 

> PLC/5 is only configured via ladder logic but can do motion control. SLC can also do motion control but the newer ControlLogix would be the recommendation if you want to do motion control. <

Agreed. The PLC5 and SLC motion control capabilities are pretty mediocre, HOWEVER, its very easy to use a seperate controller and interface to either controller, especially for fairly simple stuff.

> As far as the difference between the PLC5 and SLC, the can do both pretty we the same thing, but PLC/5 can control more I/O and faster. SLC were used alot by system integrators, because of their lower cost. One inconvenience with the SLC is that programming cannot be done on the run, but possible with the PLC/5 <

Only the low end SLCs do not allow on line programming. The SLC5/03, /04, and /05 all have on line programming. The main reason I see PLC5s being used is primarily in plants that standardized on it years ago. There is virtually nothing a PLC5 can do that a SLC cannot do in the real world and the cost is much lower.

 

A clarification: the SLC-5/03, -5/04, and -5/05 all support online programming ("programming on the run"). The SLC-5/01 and 5/02 did not, and they had many other weaknesses, too. Depending on what you are using a PLC to control, online programming can be a convenience, or downright critical.

Eric Klintworth