Which PLC for my application

jojo · May 14, 2004

PLC for monitoring / reporting data to HMI/MMI software.No control requied.

Below are I/O details:
AI: 45 ( 4~20ma)
AO: 12 ( 4~20ma) (mainly retransmission to a chart recorder)
DI: 380 (24Vdc sink)
DO: -

Mainly a HMI project for datalogging/alarming

which PLC should i choose so that it will be cost effective.

I am familiar only with AB PLC.

Thanks
jojo

SNK · May 14, 2004

It would probably help to identify what HMI/SCADA system that you are intending to talk to.

I am really more familliar with AB stuff as well, but for the numbers you are talking about....it is going to cost a fortune, considering you are not using the system for a controls-actuation. Why not use a Data-logging system or something like that??

jojo · May 14, 2004

thanks

Thanks kcarlen,
I had to display the following in the HMI/MMI
1. on/off status of motor, pump,valves(open/close),alarm(level switch high and low level) from DI
2. flow(instantaneous and totalized flow) , pressure & level from AI
3. retransmission of selected Analog inputs to Analog output card for recording by chart recorder.

HMI should be able to print alarm., trends and report generation.

I was considering to use RSVIEW32 software.

thanks

ArikBY · May 14, 2004

I would consider to use some cheap PLCs instead of one.
I think if you can divert your I\O. it will cost you less.
You dont need powerful PLC so that might work.
Some ML can do the job.

Good Luck

jojo · May 14, 2004

Micrologix 1500 with 1769-SDN, 1769-ADN

Thanks Arik,
will micrologix 1500 (1764-LRP) with 1769-SDN and 1769-ADN will be cheap for this kind of application.

I was just going through 1769-SDN manual. which says it supports 180Words of input + 180 words of output and 63 devicenet nodes.

again i have to learn about devivenet. purchase RSNetworx, 1784-PCD(pcmcia card for devicenet),devicenet cable, tap, power etc. will this all be costly.

Is there any other cheap solution for my requirement.

thanks

jojo · May 14, 2004

or should i use many micrologix 1200

Should i distribute many Mircologix 1200 on a DH485 network.
but unneccessarly i will have to pay for micrologix built in digital output and processor.

jojo

Rebuke · May 14, 2004

380 inputs? is this correct? Before choosing the Micrologix 1200 I would check the Max. available I/O. Also, you cannot online edit with Micrologix. If it is a project with a small likelihood of needing to change the program once it is running, go ahead. If it looks like you need to modify the station after launch but downtime is critical, go for an AB 503 or Omron CJI.

mordred · May 14, 2004

multiple plcs

Looks like your applcation due the number of inputs and outputs would be better served by seperating all the tasks into several zones.

then interface the data to a primary collection point. This would provide the advantage of better troubleshooting and repair If everything on this scale relied on one PLC and it crashes you could wind up with a full shutdown. We have a large scale network of PLC
in the form of LOGIX controls for our refrigeration dept. What they have done is broken it down to 24 cells running 50 input/outputs each.
then interfacing via TOTALcontrol software. This will also help lower your scan times.

you may find that OMron PLCs tend to be cheaper in price than AB

ArikBY · May 14, 2004

Jojo

I thought about combintion of ML1200 with DH485.
You need to make your calculation.about the cost

mordred

Omron is very good PLC and cheaper in price than AB personally I am big fan of Omron.BUT
for analog I|O it little bit problematic, every analog input count as 16 digital I\O.
So you need monster PLC for that.

Rebuke · May 14, 2004

"Omron is very good PLC and cheaper in price than AB personally I am big fan of Omron.BUT
for analog I|O it little bit problematic, every analog input count as 16 digital I\O."

Arik, do you mean Omron alone uses 16 bits or PLCS in general? Allen Bradley PLCS also use 16 bits for 1 analog word.

I agree that Omron is sometimes a better option if price is an issue and also that once you get used to CX programmer you may find that you may end up being quicker at it than RS lOGIX.

ArikBY · May 14, 2004

What I mean if your PLC can have 96 I\O max. for example you need 2 inputs card of 16 in and 3 card of 16 out total you have 80I\O OK.
and you want to add 2 analog inputs.YOU CAN NOT.
The analog card add 32 inputs not 2 like in AB.
Every analog in=1 16 inputs card.That the disadvantage of Omron.
I agree with you that CX is excellent programming software.
Better then RS-Logix.

BobB · May 14, 2004

I would definately look at the Omron CJ1. Very small in size and with an array of processors from 160 I/O to thousands. About the size of a cigarette packet, no rack and very powerfull.

The other handy thing is that Omron Compo Bus S (proprietary Device Net) and Device Net are mapped into high memory and do not count as normal I/O. You can use a cheap processor with a lot of remote I/O.

For a SCADA system, if you require very good trends and graphs, I would recommend Citect. It has the best trend graphs in the business. If that is not a requirement, Omron CX-Supervisor offers a very inexpensive alternative. Unlimited tags, a very powerfull scripting language, or you can use VB. Trending is quite good. Works well with DDE, OPC etc. Has been designed to use OPC.

I will have a look at your application later today and work out an inexpensive combination for you to price.

jojo · May 15, 2004

All in one panel

I forgot to tell you that all my DI/AI/AO will come to a single panel.

I am not actually distributing my PLC in many places. but if i choose multiple ML 1200 they would all sit in the same panel.

so with this which plc and scada software should i go for.

thanks
jojo

ArikBY · May 15, 2004

I agree with Bob about the CJ but if you chose CJ you need CPU for
45*16=720
12*16=182
+380
1292 I/O
It is not cheap PLC
Why you dont take I\O cards to PC save the PLC as you said you dont need control.
Look at www.ni.com
or http://www.advantech.com/

Rebuke · May 15, 2004

Also, be careful with any Compo-bus components. Make sure the Omron division of your country agrees to stock extra parts as I have been burned because of the fact that Omron stocks very little replacement parts for compo-bus in my country. On more than one occasion we've had to get parts from Japan, which is a huge delay.

Which PLC for my application

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