Set up a Master "Master"....

[Patrick]

 

Scenario :

10 stand alone machines each being controlled via ModbusRTU by a Samba 7

 

Sometimes I want to be able to take control of one, several or all of the machines through a single remote master (Vision 12.10), During this time the touchscreen input of the Samba will be disabled and will become a display only, all commands coming from the Vision.  I would like to do this over a hard wired Ethernet network.

 I have looked at the Remote operator option and it is not what I need as the commands options from the Vision will not be the same those from the Samba and must be able to be synchronized across several machines.  Effectively the Samba is becoming a slave.

 

I would be grateful if someone could confirm whether or not this is possible.

 

Thanks

[Flex727]

This should be mostly possible. As far as I know, there is no "Disable Touchscreen" function in VisiLogic, but if you write the ladder in the Samba correctly you can enable a bit from the V1210 that can prevent any actions coming from the touchscreen. That bit would have to be in series in the ladder with any touch bit on the HMI and you wouldn't be able to use the "Toggle" property of binary elements.

Bottom line, I don't see any major obstacles as long as you can update the program in the Samba.

[Patrick]

Thanks for the fast reply! 

Since I posted the question I started thinking that perhaps it would be easier to use the V1210 to trigger a reboot sequence that would set the Samba to the slave scenario, and when the V1210 has finished, then trigger a reboot back to stand alone.  Effectively have two complete subroutines

 

[Flex727]

That sounds fraught with problems to me. I would let the Samba maintain control over the 10 standalone machines, but the V1210 would deliver the commands to the Samba.

[Patrick]

Hmm, yes. I should think more before blurting out thoughts !

I also just realised that my opening post was perhaps not clear.  Each of the 10 stand alone machines has its own Samba.  The V1210  will need to take over any number of them.

[Flex727]

Ah. I thought a single Samba was controlling 10 machines. However, same principle applies.

Another issue is that you only have 4 sockets to communicate with the 10 Sambas over ethernet. It's not a problem if you only want to talk to a single Samba at a time or are willing to wait a few seconds for a command to ripple through to multiple Sambas (i.e. connect, send command, close socket, repeat for each Samba - you might have to allow for a few minutes for all 10).

[Patrick]

That won't work then.  I am going to have to rethink the whole setup

[Flex727]

Another option is to connect the V1210 to Samba1, Samba1 to Samba2, Samba2 to Samba3, and so forth. With that setup you can ripple a command out to all 10 easily in less than a second. I've done this many times and it works well.

[Patrick]

Connect with modbus TCP?

[Flex727]

Yes, MODBUS TCP. Under the scheme I mentioned, the V1210 would be Master to Samba1 Slave, Samba1 would be Master to Samba2 Slave, Samba2 would be Master to Samba3, etc. The PLCs can easily act as both Master and Slave simultaneously on two different sockets.