Modbus and Ethernet on Logix5000

Hi Guys!

Since I have been a fix with protocols not being the same before, I'll ask if any of you have ever tried this combination:

I have a system with a 1756-L62 CPU and a 1756-ENBT Ethernet module.
On this system I have 17 silo's that needs a new level meassurement, and for this I have chosen VEGAFLEX 61. To cut down the number of analog inputs required, the vendor suggests that I use a VEGASCAN 693. This scanner can read up to 15 sensor values over a single 2-wire cable - neat!

But it communicates over Ethernet using Modbus protocol, and this is where I start getting nervous ;-).
Is this modbus protocol the same as what the Logix platform uses and can it communicate with the scanner at all?

Regards,

Michal Rudbeck-Rønne

Hello Michael;

The Controllogix ENET cards support Ethernet/IP; they cannot handle Modbus/TCP without some form of converter/gateway.
One suggestion: Go to www.prosoft-technology.com amd look at their 1756-MNET line of Modbus/TCP communication modules for the Controllogix platform. They are easy to setup, PLC code is provided for the handling of data, and a configuration package makes setting up the network very easily. Price is about the same as an ENET module.
Hoep this helps,
Daniel Chartier

Hi Daniel!


Thanks!

Yes it helps, but as the system I have is already running it might be the same price if I simply connect all sensors to analog inputs.

The scanner can be supplied with DeviceNet comm too, but a DeviceNet scanner to my system will also be around 2100 US. And then it would be as good to wire each sensor up on it's own.

But I'll have a look at that module and see what price we end up with.

Regards,

Michal Rudbeck-Rønne

The 1756-MNET card is confusing and expensive. I'd use a Red Lion Data Station Plus. Its $ 499 USD and nearly moron-proof.