Dear Sirs,

First of all, let me introduce myself. I'm a Software Engineer in charge of protocol interface development. I work in a company that produces weight devices, focusing the automation/industrial fields.

I found your e-mail in the web
(http://remote.control.com/mhonarc/msg11451.html) while I was looking for some information regarding ModBus Plus protocol.

Recently, I've developed a standard ModBus interface in our equipments in order to communicate with PLCs devices in industrial plants. However, there are some companies that are asking me regarding ModBus Plus but unfortunately I have no information in order to give them the proper support.

What I'm looking for is:

1. What is ModBus Plus?

2. What are the main differences between ModBus and ModBus Plus?

3. Is there any specific protocol to support ModBus Plus or that one that I've developed (standard ModBus) can be used to deal with?

4. Is there any specific hardware/physical feature that need to be implemented in order to launch the ModBus Plus protocol?

Please, let me know if I'm being clear in my explanations. If don't, please, let me hear from you.

Feel free to get in contact with me if you need further information.

Best regards,

Xavier F. Albornoz
ALFA Instrumentos Eletr=F4nicos=20
+55 11 858-2299 x220/221

 

Dear Xaviar,

Modbus Plus is Peer-to-Peer network protocol with nodes (max 64). I have detailed description of Modbus PLUS protocol on some of my CD's. In basic, that protocol is MODBUS (using same command) but without address and checksum field in standard Modbus message. Instead of that Modbus PLUS use networks addressing schemas. Modbus PLUS have speed 1Mb/s, token passing IEEE 802.4 (logical "token ring")protocol. If I understand , you want to connect Modbus device to Modbus PLUS (MB+) network or device on MB+. Simple solution is that you buy MB+ BRIDGE MUX which have 4 Modbus ports and one MB+ port and connect your MODBUS Device to that port.I think that you have on that MB+ Bridge RS232/RS485 Modbus port (www.modicon.com)
Like you see Modbus is Master-Slave protocol and Modbus PLUS is Peer-to-Peer protocol. In Modbus network you have one master and up to 255 slaves but in Modbus PLUS network every device (NODE)may be master or slave (depends of network current state).
If you want to make your Modbus PLUS interface (I think that MB+ use some specific Chip-ASIC) you must contact people from Modicon (USA)to order that chip. I have expirience with MB+ module on AC Motor Drive (Control Techniques-UK)which have interface card for that net and some MB+ driver which you must download with application program......

That's for start, if You want I may you send you more (.pdf files, doc, ppt...)

Excuse me for bad English ! That theme, about Modicon and Modbus,MB+ is my favorite theme but unfortunately I stopped working on that, because I was living in Yugoslavia and now (in Czech) I must working with another things (electronics hardware...)
Best Regards,

Sasa Vukanovic, B.Sc.E.E.
+42 0604 569 749
Prague, Czech Republic

 

>1. What is ModBus Plus?
MB+ is a based on RS485 - It is a MODICON ASIC chip set.

>2. What are the main differences between ModBus and ModBus Plus?
The protocol is the same, MODBUS.
MB+ is a token rotating 1 megabit network 20 000 registers per second and as I said before an ASIC chip set.
Modbus is loosely term the RS232 master/slave setup, but can run on standard RS485, radio and ethernet.

>3. Is there any specific protocol to support ModBus Plus or that one that I've developed (standard ModBus) can be used to deal with?
Any Modconnect partner, now Schneider Alliances partner can purchase the chipset.
Hunt around http://www.modicon.com on how to get access.

>4. Is there any specific hardware/physical feature that need to beimplemented in order to launch the ModBus Plus protocol?
The chipset.

Regards
Rob E.

 

I'd like to get more (.pdf files, doc, ppt..)
about Modbus+. I work with modbus device and also must to interface it with MB+ devices.
Regards.
Malkin Lev
Software engineer
Jerusalem, Israel