Bently Nevada 3500 - Modbus communication


Thread Starter

Kelly Baker

I am developing comms for this device on ControlLogix, and I need to know which Modbus registers hold which data for these modules. The manuals do not give clear answers to this, as they are geared for use with the software provided by Bently Nevada. I am going to call support tomorrow if nobody here can help, but I was hoping to get some direction sooner.

Thanks in advance,
Kelly Baker
Bently uses Modbus protocol as you stated, but Allen Bradly Controllogix PLC uses its own DF1 protocol. The two serial protocols are not compatible.

You can install a Prosoft card like the MVI56-MCM into the Controllogix rack and then configure it as a Modbus Master. Then you can read Bently data.

I have experience in this arena since I have done this kind of interface many times over.

Email me should you want more details.

Tom. Tran @ Industran. com

Carlos De Abreu

Like said Tom.
1. you will need to instal a MVI56-MCM (controlLogix chassis)or MVI94-MCM (Flex I/O chassis) to conect with 3500 Bently system. These modules have a setup jumper (Rs-232 or Rs-485). You must mach it with Bently Nevada configuration setting. See below

2. Using the Bently software you must program the Bently's communications module. Baud rate, bit stop, Rs-485 or Rs232, and the modbus registes address.

3. To config the MVI56-MCM or MVI94-MCM. Baud rate, master, code function, and the Mobdus address to read to Bently system. More detail you will read the manual. The manufacture is Prosoft.

4. Implent logic in the PLC Contrologix. It will depend with kind of module you will use. See the manual too.

The first time the job is not easy, and is impossible give you every detail. But using the general lines described above and the manual, you can do it.

Good Luck
Dear Tom,

I will upgrade the system to 3500 and I am currently using RS 232 to connect with DCS. How to configure the system (addressing) that will match with the DCS system addressing?

So did you get a Prosoft card for the Allen Bradley PLC rack?

Or are you connecting Bently 3500 to a DCS instead? Please specify which DCS?

If you are bringing the data into the DCS directly, then The settings b/w the Bently and the DCS have to match

1. Connection type (RS232 or RS485)
2. Baud rate (9600 for exmaple)
3. Number of bits (8 for example)
4. Parity (odd for example)
5. Stop bit (1 or 2)

If the connection is RS232, then the cable limitation is 50ft.

If the connection is RS485 then the cable length is limited to 4000 ft.

If the 3500/92 module you use has an Ethernet port, then you can even use Modbus TCP to talk to Bently?

Email me the make and model of the DCS and I can help you with the cable pinout.

Usually, you

1. find out the setting in the Bently 3500 by using the Rack Configurator software

2. Change the DCS comm port to match the setting in the Bently 3500.

It helps if I know

3. What brand and model of the DCS are you using?
4. Where is the interface point? Direct connection to the DCS or via Modbus
Ethernet Device Server?

Good Luck,

Tom Tran
[email protected]
> Bentley Nevada 3500 gateway to Prosoft MV156E-MNET communications Issues

I am a controls Engineer here at CH sugar Refinery in California. I read your post and I am experiencing issues with the communications. Prosoft is having me Wireshark the Modbus32 connections so they can try and determine the issues. Any help will be greatly appreciated.

> Email me should you want more details.

> Tom. Tran @ Industran. com
Did you get this issue resolved? The reason I ask is because I ran in to a similar issue a while back. It turns out that the Bentley vibration monitors did not like the way the MNET module opens/closes sockets so fast.

One fix was to add a poll delay, which isn't what we wanted to do.

The best fix was to update the firmware (they should send it to you for free) to a MVI56E-MNETC and use independent client connections for each vibration monitor. This sped things up and got rid of all comms errors.