CANopen

What do you guys think about CANopen. From what I have read up on it is a good solid bus with up to 5k distance, albeit at only 10k transmission speed, but as am I new to it thought I'd ask the question.

I am currently looking at a project with 19 devices controlling automatic gates/bollards over a bus length of about 600m, so am having to split into to CAN buses on separate PLCs that then hook up to a screen through ethernet. One of the PLCs is also going to be connected to a PLC of a different manufacturer by RS485 with ASCII control.

Does anyone know of a better way of doing it. Using fibre is out cause I want to keep it as simple as possible.

Not sure what your gates require to open/close but I wouln't think you'd need a PLC at each location. I would look first at remote I/O drops on Canopen.

I've used one HMI on CAnopen and wouldn't recommend it. Even Modbus is a much better way to go for that. However, the remote I/O is fast and efficient and, as you mentioned, can go long distances if you are willing to forgo some speed.

Like anything with a lot of power, there can be a bit of a learning curve. I can recommend the book Embedded Networking with CAN and CANopen by Pfeiffer, Ayre, and Keydel ISBN 0-929392-78-7.

<Disclaimer - Prodcts I sell follow>
Moeller has a line of plc's called the X-Contrl which all have built in CANopen masters. The XC-200 line also has onboard ethernet which you mentioned you might need. You can see more here:
http://www.moeller.co.uk/xc200.htm

The RS485 could be done with a serial expansion card.

Programming is IEC61131 based on the CoDeSys system.

Hope this helps

Sorry, didn't explain very well. There is a remote O/I drop at each location. I am using Telemcanique OTB modules at the gates with two Twido PLCs, at a central point, both running with a master CANopen module to create the two networks due to the 16 device limit on CAN.

These PLCs are connected to each other and an HMI using an ethernet router.

The RS485 is wired to a plug on card on one of the PLCs to connect an existing Idec PLC via fibre that is already present.

CANopen?

I like my can-open-er!

With CANopen, PLC open, open programming, AmEx Open, anything open, it just doesn't seen like a good thing to me.

The 16 node limit must be imposed by the Twido. True CanOpen has the capability of 127 nodes.


Casey: Your trap is open.