New to PLCs, specific project, need advice

[JesperMP]

I know that others are suggesting different approaches, but maybe OPC + JAVA is the "clever" solution.
OPC is platform independent, so if you create a solution that supports OPC, you will not be tied into any specific brand.
Look at this page for Java clints for OPC:
http://www.opcconnect.com/java.php

 

[plc_user1973]

Triangle PLC has an expansion boards to add to accomodate your need of so many switches plus you can network several plcs together on the 485 drop. For simple on/off switching this is the best way to go.

Although you may think the product looks difficult because of where they have been used, do not get scared, they are easy to program. Download the simulator and check it out.

The tech-support is great here in the US.

 

[pinworm21]

Okay......

Few questions......

You said you need a few hundred I/O. What is the topology of everything....one I/O card per floor or multiple I/O cards per floor ?

Do you need just digital inputs or will you need some outputs also ?

Is this a one time project or is this something that your going to be doing a lot of these systems ? If it is a small limited project then a PLC or an I/O card would be fine. If it is something that you might be doing a lot of then you might want to look into getting a custom I/O board built.

What do you need for an interface ? RS485, USB, ETHERNET, ETC ? Going by my past experience it would be best to use RS485 to all the I/O cards and then tie into a main I/O device that has ETHERNET or USB, Unless there are ETHERNET ports throughout the building you can tie into with each I/O board.

I think that a small PLC would work great and would be cost effective if this is a one time only job or small quanity, Otherwise I would look into a custom I/O board (Maybe a PicMicro processor with some multiplexed inputs) only because I think a PLC might be overkill, Although a cheap PLC would work great in both cases. Entertron PLC's seem to be cost effective and they can even modify their I/O to suit your needs.


Dave

 

[BretB]

Jesper, thanks for the web-site. That looks like it will work.

 

[ndzied1]

Not sure if this helps but worth a look:

http://www.opcconnect.com/java.php

 

[BretB]

PLCuser, I checked out tri-plc's web-site. Their stuff looks good.

I also checked out Entertron's web-site (pinworm) and their products actually seem very good, and a lot like what I need. Do you use Entertron PLCs?

I was looking at Automation Direct, but some of the literature on their web-site is steering me toward the Entertron equipment. It seems smarter and more flexible. Though there were no prices listed, which makes me think they are spendy. The AD was good because I could get what I needed for testing purposes, 20 I/O to one computer for a few hundred bucks.

As far as the size and topology of our project goes, in the end it's big. Meaning right now, I need 20 I/O going to one computer just for testing the software we are developing. The I/O is a small part of a larger system we are developing. The initial implementation of the I/Os will be over three floors of a hotel building, looking at about 150 room doors to see if they are occupied or not, based on switches by each of the doors. Those signals need to all go to the central computer, which gets all of the statuses of the doors and posts them as needed in our overall system. There are no predicted uses for a direct PLC output. For instance, right now, these rooms are monitored with AD PLCs which were put in about eight years ago, that show up in lightbulbs on several boards. Those are actual PLC outputs from what I know. In the system we are building, we just want all the data to go into our computer and we will handle the function of the lightbulbs in our system.

As far as RS485, USB, ETHERNET, ETC, I think ethernet is what we will use as it seems the most simple and compatible, unless there is some reason to use otherwise.

On another note, I did check out the OPCConnect/Java site. Thanks. That is good. With that I am confident that I just need to buy the hardware, and whatever it may be, we can easily solve getting the I/O signal into the computer. It is becoming more and more clear that there are many solutions to any kind of problem with I/O.

- Bret

 

[BretB]

[font=Arial, Helvetica, sans-serif]I am posting here the hardware that I have spec'ed to be bought next week for anyone to comment on as far as workability or anything else.

Please note: this equipment is intended for development and testing purposes, I know that this will not reach all 100+ switches that I will have to reach when we impement our system.

Also please note that these are Automation Direct specifications, I hope it is general enough to communicate to those non-AD users as well. If there are any other brands out there that would have something comparable, my ears are open...

DL 205 4-slot base
H2EBC Ethernet Base Controller
16ND3-2 DC Input (16 inputs)
PSP24-024s Power supply

- Bret
[/font]

 

[Stephen Luft]

Bret,

By way of introduction my name is Stephen...I am a representative for Entertron. (mentioned in a previous post)

We have a couple of options available to you.

Based on what you are seeking from Automation Direct, our SK1600-RIC should be sufficent in that it will do up to 32 digital inputs and includes a 12 VDC @ 1 amp power supply. www.entertron.com/sk1600ric.htm

Should you require more digital inputs, the Elite-2000 is available. www.entertron.com/elite.htm

Unfortunately, we don't do Ethernet directly but have worked with various Ethernet to serial converters. An item such as:

http://www.bb-elec.com/product_family.asp?FamilyId=2&TrailType=Sub&Trail=1

The ESP901 should be sufficient.

When you get an opportunity, if you are interested, feel free to contact us, so that I may obtain additional information regarding your application and company...to see what is the best approach for setting you up as a customer.

Hope this helps.

God Bless,