When a PLC is already connected to one TOP via serial (RS-232C/RS-422/RS-485) and you want to add additional TOP units without changing the PLC wiring, use MBUS.

 

 

What is MBUS?
MBUS enables N:1 communication—one controller (PLC) over serial, shared by multiple TOP HMIs via Ethernet—with simple configuration.

-. The first TOP that is physically connected to the PLC over serial is the [MBUS Server].
-. The additional TOP units (2nd, 3rd, 4th, …) connect to the Server over Ethernet and act as [MBUS Client].
-. There is no hard limit on the number of Clients, but performance decreases as more are added. We recommend 4 or fewer Clients for stable speed.

 

 

Project Compatibility
As long as the PLC model/settings selected in TDS ([Project] - [Property]) are the same across the TOP projects, MBUS will work.

 

The projects do not need to be identical in every detail.

 

 

 

A. MBUS Server (TOP #1 connected to the PLC via serial)
1. On the TOP HMI, open the menu: [Control Panel] - [Service] - [MBUS]. 
    (Use the Exit button on the top menu to reach the TOP menu screen.)
2. Enable [Use MBUS Server].
3. Select and configure the serial port that communicates with the PLC.

 

B. MBUS Clients (TOP #2, #3, #4, … over Ethernet)
1. On each Client TOP, go to [Control Panel] - [Service] - [MBUS].
2. Enable [Use MBUS Client].
3. Enter the IP address of the MBUS Server (TOP #1).

 

[Figure. MBUS Client]
 

 

 

Notes
-. TOP-VIEW does not support MBUS.
-. Clients communicate with the PLC through the MBUS Server over Ethernet; the PLC remains connected only to the Server via serial.
-. For best performance, keep Client count ≤ 4. (More clients, lower speed)