Networking CPM2A with PC

[ahuat 0]

Dear All, i am planning to built a small plc network, and i am choose to use 3 unit CPM2A PLC because of they have two ports, 3 unit NS5 for each PLC, 3 unit RS232/422 adapter, and a normal PC used for take data from each PLC every five minutes. In the PC i use DDE manager which already installed during my CX programmer installation. What i need to know is, does anyone already has experience with this system? Does the system stable enough ? I mean less communication problem between PLC and PC? Anybody has a manual how the PC make a 'reading' from one PLC to another PLC? Regards Ahuat

[Nibroc 4]

Ahuat, (A penny for my thoughts ...) I personally would not recommend your architecture: 1. The PC would act as a master, and as well as logging etc it would be required to pass data between PLC's - this is not a robust solution (PC's running windows are not reliable) 2. To program the PLC's, you would need to disconnect either the NS screen or PC link cable - there is no way to program without some sort of shutdown of the system. 3. Each node (NS, PLC, PC) has limited connectivity to the other nodes (eg the NS connected to CPM2 1, cannot directly communicate with CPM2 2 etc. Five years ago, this solution may have been considered OK however: A much better architecture would be: 1. 3x CP1H PLC's with CJ1W-ETN21 ethernet units connected. 2. 1x PC 3. 3x NS HMI's with ethernet option 4. ethernet switch 5. 1x CX-Supervisor software for data logging on the PC Although more expensive this solution is far superior: 1.Any NS can communicate with any PLC (so one NS application does all) 2.Any PLC can communicate with any PLC 3.The PC can communicate with any PLC 4.The PC could be used for programming of any PLC/HMI from the single point 5.A programming 'laptop' can be plugged in anywhere on the LAN (install extra RJ45 sockets at handy places or install a WiFi access point) for programming of any PLC/HMI. 6.Communications performance of this system will be superior to the serial system you have suggested. 7.CPM2 series PLC have been superceded and are now 'out of date' 8.The CX-Supervisor software does not require specialist knowledge of communications protocols to configure 9.Maintenance and trouble shooting will be easier 10.Remote access via the internet can be implemented All of the above devices can communicate concurrently accross the same single network. Nibroc Edited 19 Oct 2007 by Nibroc

[ahuat 0]

To Nibroc, Thank you for your recomendation. Looks cost much more of money, but looks still acceptable. I don't have cx supervisor, but i have Lab View 8.0, it works well with National Instruments product, but i have no experience with Omron. Regards, ahuat