Basic M340 Capabilities Question

[Ken Roach]

I'm investigating a machine that uses Modicon M340 controllers, but I have no experience with those models and hope I can get some general advice.

The CPU is a BMX P34 2020, whose prominent features are "1024 discrete I/O, 256 analog I/O, Modbus, and Ethernet", according to the Schneider website.

I've been able to open up the Unity Pro XL software and see that there is an IO Scanning feature for the onboard Ethernet port, but that's where my experience stops.

I'd like to be able to control an Altivar 71 AC drive, and some Turck BL67 analog Input modules (with a BL67 network adapter with Modbus/TCP).

Does the M340 model P34 2020 support such "I/O Scanning" features on its built-in Ethernet port ? Is the protocol ordinary Modbus/TCP, or is there some special Ethernet protocol specific to the M340 family ?

 

[justblaze]

I am not an expert on these but I have heard that the on board port does not do IO Scanning. You need a NOE or NOC ethernet module. I do believe the NOE is being phased out so the NOC should be your choice.

Edit: Look into this thread.

http://www.plctalk.net/qanda/showthread.php?t=92723

 

[Lare]

M340 inbuild ethernet port don't support IO-scanning. You need separete NOE card for scannning.

You still can use READ/Write_Var blocks and communicate via inbuild Ethernet port. There is little bit more work with PLC program that way.

 

[Saffa]

As Lare said, you will need an NOE or one of the newer NOC cards.

The ease of doing IOScanning using the NOE card makes it worth the investment, especially if you have multiple drives or devices with the same type of data to read / write.

If you use read var etc instead then there's a couple hours work the first time round to build yourself a little polling routine that can handle comms loss and flag an alarm etc.

 

[V0N_hydro]

Here is the polling routine I have been using for the past few years for modbus master using the CPU ethernet port:
http://www.plctalk.net/qanda/showpost.php?p=549955&postcount=4

However I usually get the NOE module unless the data is just for display and logging.

 

[Ken Roach]

Thanks, guys, for the quick and experienced information.

This system is already complex with regard to communication; it has 18 CoDeSys-based controllers (two different brands) in addition to the two M340's, and the amount of Modbus/TCP messaging and mapping and translation is already substantial.

So if I can buy some simplicity and performance for the price of a network module, I'll do it.

There will be, I'm sure, some more questions from me on this topic, so I thank folks for their input on this and on other things, in advance.

 

[Lare]

Max configurable ethernet ports for M340 2020 is 3 (inbuild + 2 separater cards)

p.s Corrected amount of cards