Quantum to Quantum


Thread Starter


Hi all! I'm new in the list.
I need to connect a two Modicon TSX Quantum PLC's via leased telephone line (5 km). At the one side I have one Modicon TSX Quantum PLC and on the other side I have Modbus Plus network with one Modicon TSX Quantum PLC, Magelis operator panel and SCADA system. Communication between SCADA system and first PLC have to work independent on the PLC at the SCADA side. Is it possible to connect Modicon TSX Quantum on the Modbus Plus
network via telephone lines (included other equipment)? If is not, can anybody give me some other solution.


Ivan Lorencin,
Ljubljana, Slovenia
[email protected]

Pierre Hinse CET

Get a BM85-000 on the side with the MB+ connect the MB+ port to your MB+ network.

Connect a lease line modem to onee of the serial ports on the BM85. At the other end (the PLC) connect the Mobbus port to a leased line modem.

Voila all done.

(you will have to the instructions on the BM85, to configure it so it passes BM+ request out the serial port.)

Pierre Hinse
Sudbury, Canada
I think you can use BM85, a bridge of MB+ to MB,on the MB+ network at Scada system, so you can conect the MB port of Quantum at remote side to the MB port of BM 85 via leased phone line(modem is also needed), the Quantum on the Scada side can read and write the data of remote Quantum through this way.

If you want a cheap solution a Momentum with MB+ and MB can also do.

Kenneth Schunk

Several methods come to mind.

The first problem you will run into is getting the MB+ onto the leased line. MB+ is physically an RS-485 network, but the speed is probably far too high to go across the leased line directly.

One method would be to use the MB+ bridge (NWBM85C002) to convert the MB+ to Modbus. At the remote end you could connect directly to the Modbus port on the PLC, or you could convert back to MB+ with another bridge.

A less expensive method would be to put a Momentum PLC at the site with the SCADA. Connect the Momentum to the MB+ network, and use the XMIT block in logic to talk with the remote Quantum system. It would be less expensive hardware, at the cost of anther program to write.

The bridge would be my choice of the two, but be warned - it's not cheap. US list price for the bridge is $3165. The C002 version is a dual MB+ bridge - they stopped making the single cable version (NWBM85000), but it would be cheaper if you could find one.

Good luck.

Sasa Vukanovic

Hi Ivan,

Quantum PLC (CPU)have default one MB+ port (with one Modbus port). You may use, for leased line Modbus modem for leased line (I think that is in the Modicon standard price list). You haven't use directly MB+ on that distance (max with repeater and MB+ cable is about 500 m) but you may use Modbus modem . If you want directly connect Magelis (MB+ PCMCIA interface card))to distant PLC you may use MUX Bridge to convert message from MB+ to MB , with (Modbus Leased line)modem and on the end, MB modem to distance PLC. Another solution is that you use two modems on one side and two modem on another side where is one line for messages from PLC1(or Magelis with MUX) to PLC2 and second line for messages from PLC2 to PLC1 (because Modbus is Master-Slave communication).

Sasa Vukanovic, B.Sc.E.E.
+42 0604 569749
Prague , Czech Rep.
You will need RS232 Modems on Both Ends of the leased line. On the Scada Side connect the Modem to a Bridge Mux. The Modem is connected to one of 4 RS232 ports on the Bridge Mux. The Quantum PLC on the Scada side will act as a Modbus Master Device by using the MSTR command block. The Bridge will convert the Modbus Plus message to Modbus and send out the Port which needs to be configured in the Bridge as a Modbus Slave Port.

The Modem you get needs to be able to handle 11 bit words

1 start 8 data(rtu) 1 parity and 1 stop.

Bob Moors

Steve McAlpin

Yes, all you have to do is hang a bridgemux off your modbus+ network and communicate out your lease lines via modbus to the other Quantum. I have a 40 plc remote network set up this way.
Hi Ivan.

I've used the BM85 bridge mux to exchange data with modicon PLCs (and other modbus slaves).

The BM85 connects to the MB+ port on the main Quantum and has 4 modbus port

each port can be connected to a modbus device or network. the distance suggest the need for some sort of modem.

use the MSTR function to send/receive register from the other Quantum.


Rob Entzinger Schneider Automation

You can use the XMIT loadable to communicate tween two quantums, direct or via telephone modems(hayes compatible) there is are bits one can set to use hayes commands, MODBUS and/or ASCII transfers.

Rob E.

Kenneth Schunk

That solution misses the statement in the original post:

...Communication between SCADA system and first PLC have to work independent on the PLC at the SCADA side...

which means that NONE of the XMIT / Modbus Port Bridge Mode solutions would work. If is comm path is MB+ he needs an external bridge (the BM85), and if he can use MB via a serial port from the SCADA system he can use leased line modems. Note that since the Magelis screen can't do both MB+ and MB at the same time the second solution would not allow data from the remote PLC to be easily displayed on the Magelis.