Difference betweeen PLC & PAC

anks

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What is the difference between PLC (SLC500, PLC5, Micrologix etc) and Programmable automation controllers (SoftLogix, ControlLogix etc)

Can I use SCADA system more conviniently with Prog. Automation Controllers than the above PLCs??

Thanks
 
anks said:
What is the difference between PLC (SLC500, PLC5, Micrologix etc) and Programmable automation controllers (SoftLogix, ControlLogix etc)

Can I use SCADA system more conviniently with Prog. Automation Controllers than the above PLCs??

Thanks

The PACs are the flagship products for Allen Bradley.
The PACs will continue to evolve & develop, with better features & whatnot then the PLCs.

If I have a choice, it's always the PACs. You can actually get a system on the PACs cheaper then the PLCs in some cases.

For higher level communication, the PACs are far superior then the PLCs.
 
Basically, we have 5 sites witihn 25 mile radius which are hooked to a wonderware SCADA system, now we are adding few control valves & analog transmitter on each sites, I was wondering if I can only use 1 controller to control all 5 sites using remote I/Os????? the thing is customer wants HMI screen at each site, can I achieve my controls with 1 controller (probably SLC500) because we have RSLOGIX500 or does I need to go for PACs????

Thanks
 
The difference between a PLC (Programmable Logic Controller) and a PAC (Pogrammable Automation Controller) is the size of the marketing budget.

National Instruments, Allen Bradley, GE, and others are trying to create market differentiation for their high end PLC products by calling them PACs. As far as I can tell they are simply high end PLCs. Sure, some of them have some advanced features, but so do high end PLCs!

To quote Mrs. Shakespeare's little boy Billy, "What s in a name? That which we call a rose By any other name would smell as sweet."
 
anks said:
Basically, we have 5 sites witihn 25 mile radius which are hooked to a wonderware SCADA system, now we are adding few control valves & analog transmitter on each sites, I was wondering if I can only use 1 controller to control all 5 sites using remote I/Os????? the thing is customer wants HMI screen at each site, can I achieve my controls with 1 controller (probably SLC500) because we have RSLOGIX500 or does I need to go for PACs????

Thanks


In this case, I'd want a PLC/PAC in each location. You would need a VPN set up to make the communications work, but the overall system would be much more capable.

The remote I/O would be a trick through VPN. Not a risk I'd want to take. It could be done, but its risky. You would be depending on your ISP, as much as your controls. I don't trust Internet Providers.

Last time I checked Control Logix could be very competitive price wise to the SLC 505. For process controls, no question, the Control Logix is much better. Better math, faster, and cheap too.
 
I thought that I might be able to use the existing SCADA system and control the instruments through single controller.

Thanks
 
Just for the record, I really hate the idea of controlling I/O remotely (not, as in the other end of a machine, but as in completely off-site).

No matter what link method you use, it will one day die; and any process that is being controlled will wander off into uncontrolled la-la land.

Using AB, an excellent compromise might be to use a main, supervisory ControlLogix processor, and then for the remote sites, use either CompactLogix or FlexLogix. That way, when the comms link does die, the local nodes will still act autonomously. Link it all together through VPN or some other scheme to your SCADA system.

IMHO only
 
rdrast said:
Just for the record, I really hate the idea of controlling I/O remotely (not, as in the other end of a machine, but as in completely off-site).

No matter what link method you use, it will one day die; and any process that is being controlled will wander off into uncontrolled la-la land.

Using AB, an excellent compromise might be to use a main, supervisory ControlLogix processor, and then for the remote sites, use either CompactLogix or FlexLogix. That way, when the comms link does die, the local nodes will still act autonomously. Link it all together through VPN or some other scheme to your SCADA system.

IMHO only

you're right. A centralized control point can easily be put out of commission and then everything else will just stop. Better just to make it supervisory with always the thought that it could get disconnected.
 

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