M340 and Altivar 71 over Modbus/TCP

I'm getting involved in a project that uses Modicon M340 PLC controllers and Telemecanique/Schneider Altivar 71 variable-frequency AC drives. As most of you know, I'm an Allen-Bradley expert but a newbie with Telemecanique/Schneider/Modicon.

Right now the drive is connected to the PLC purely with discrete I/O; the PLC sends the drive a Start, Stop, and two Speed Select inputs.

There's a totally separate contact wheel encoder connected to a BMX EHC 0200 counter module in the M340 controller chassis, and one of my tasks is to figure out how the original programmer used them together.

My brief inspection showed only a 'Modbus HMI' plug on the front of the Altivar 71.

From what I've read, I can connect the Altivar 71 to a Modbus/TCP network using a "VW3 A3 310" module, which fits on the face of the drive and looks like it allows that Modbus HMI port to pass through it. The Ethernet plug itself faces down, on the right center portion of the option board.

My first question is whether the Altivar 71 can be run like a Remote I/O device by the M340, or whether I have to write logic to explicitly send message instructions to it repeatedly.

My second question is about the discrete inputs for speed selection. Do two physical inputs give me two selectable speeds, or four selectable speeds as a binary number (00, 01, 10, 11) ?

I think I figured out the answer to the second question: I found an Altivar 71 Programming Manual that says

2, 4, 8 or 16 speeds can be preset, requiring 1, 2, 3 or 4 logic inputs respectively.

Click to expand...

Exactly how the speeds are set up, and how the original programmer used them, is what I'm being hired to do.

Regarding the first question, I *think* that the M340 can do remote I/O over Ethernet using the Modbus/TCP protocol, but I'm not sure how everything is set up in this system.

There are also Lexium LMC20 motion controllers and a bunch of Turck BL67 EN-GW gateways with I/O modules on them and nobody seems to know if the M340 or the LMC20 is in charge of them.

The M340 platform can scan IO on Ethernet, depending on the Ethernet module you choose:

ModbusTCP on an NOE
ModbusTCP or EtherNet/IP Class1 on a NOC

I think the EtherNet/IP card on an Altivar 71 is a different card (but from memory, the ATV32 drive card is either protocol). So if you have a card, then the supported protocol is fixed. Note the embedded port on the M340 CPUs can not 'scan' IO over Ethernet - it can only do explicit ModbusTCP messaging through logic. Since you are coming from AB, I think you will find some of the messaging on Schneider quite archaic - the MSG instruction in either RSLogix500 or 5K is much easier to use. In fact, for the NOC modules which are dual stack, it's down right disgusting what they expect me to know to use the block to send an explicit EtherNet/IP message!

Schneider calls IO over ModbusTCP 'IOScanner'. In the newer dual-stack modules, I think they call it either Modbus Scanner or EtherNet/IP scanner. In any case, as you would expect, no logic is required for scanning functionality.

I recall using IOScanner with a Turck gateway some time ago (not the programmable one, but the IO-only variant on ModbusTCP with IOScanner) and had some issues with the TCP connections. Just something to watch out for if the system is not operating correctly.

Ken

The ideal way to communicate with any ethernet device is to use io scanning. You just fill out the io scanning table which will set up all the comms. But an M340 would require a NOE module to have this functionality (the in built CPU ethernet port does not have this service). So if there is no NOE module then you will need explicit messaging (Read_Var Write_Var)
I would think the gateways are also IO scanned

The IO scanning table is setup in UnityPro in the project browser window in the communication folder

You are correct about the module for the Altivar, hmi port passed through (this is just a standard Modbus port) and the ethernet port (or ports depending on Module) are on the bottom
You can use SoMove software to setup the drive (it is a free download from the Schneider site

Outstanding advice, guys. You saved me from the fundamental mistake of thinking that the built-in Ethernet port on the M340 controller would perform IO Scanning. Buying an NOE module to avoid relying on a complicated instruction makes sense. It may also give me some easier connectivity to the Lexium motion controllers.

I have one unused slot in the 8-slot chassis. Can the NOE module be in any slot ?

The SoMove software is a new name. Is it different from PowerSuite ? That's what I've read about for basic configuration of Altivar 71 drives.

If memory serves me correctly you can have a NOE card in any slot but no more than two total in one rack.

From what I've read in the "Modicon M340 for Ethernet Communication Modules and Processors" manual, the NOE 0110 module has a bunch of extended features like custom user web pages and extended diagnostic functions.

If all I want to do is some I/O scanning of a couple of drives, is the BMX NOE 0100 module the appropriate unit ?

yes for I/O scanning the NOE 0100 is perfect

SoMove is the replacement for PowerSuite.
SoMove is what is used to configure any Schneider drive

And yes a NOE or NOC module may be placed in any slot of the primary rack.
The NOE0100 would be all that you require for IO scanning any Modbus TCP device.
Just for your reference a NOC module will do both ModbusTCP and EthernetIP it also comes complete with 4 ports, 2 of which may be configured to manage a redundant ring configuration, so in many cases you don't even need a switch

Just to add - the last time I bought, the NOC was a little cheaper. My guess is they are working on phasing out the NOEs, so adjusting the pricing accordingly.

I can send you pre-built fbd from schneider for controlling an atv71 over modbus tcp/ip
Just pm me as i think i got the block of their alliance site so cant give you the link

hi everybody. i have a problem exactly like this but with altivar61 and modbus RTU protocol. is there anyone can help me how to use read_var blocks for reading from 16xatv61. i have used lu9gc3 modbus hub.but when i connect more than 4 or 5 slave to the m340 cpu the sercom led will off and communication will lost.i think i have an error in using read_var or using lu9gc3. i,m confused. maybe it is because of noise of drives or .........
thank you all buddies

I believe VonHydro have replied to you on other section

Greetings Ken Roach and Everyone...
I'm looking for the PINOUT for the cable set for the Altivar Drives. In particular a client has an Altivar 71. I found this set that Schneider peddles: VW3A8106
http://www.ebay.com/itm/SCHNEIDER-E...ar-/381017830432?_trksid=p2141725.m3641.l6368
I'd like to build my own if I can find the PINOUT.

The Altivar on TCPIP or more correctly ModBusTCP will communicate via two blocks of memory.
The input will have about six words and the output the same

The drive addresses various words to the io words.
Two you will have to use are the input and output command words and then you can use speed command input. running speed etc power ,amps ans so forth.