adccommunitymod (AutomationDirect) asked a question.
Confused
Created Date: May 15,2007
Created By: twbrock
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Now I'm confused see post ‘New Network' After reading many posts I have more questions than answers If I use 4 D0-06's and 1 C-More commutating over RS-485/Modbus can I monitor or report to the C-More from all PLC's Does multi drop mean daisy chain? Or can the multi-drop be a Y? Do I have to make one of the 06's the master and have it pole the others and store the information to output to the C-More?
Created Date: May 15,2007
Created by: Steve Bailey
One C-More can communicate with multiple DL06 PLCs. You will need to set up four "Devices " under the COM port in the Panel manager. Each of these devices will need to have a different PLC Slave number. Each of the PLCs will need to be a Modbus slave and have an ID number corresponding to one of the four devices. There can only be one master on the multi-drop network. That has to be the C-More.
Your cabling will need to be a daisy chain with terminating resistors at the physical ends of the wires.
With four devices on the network, be sure to pay careful attention to the addresses of the data from each PLC. If necessary, you should include ladder logic to move your data into consecutive memory addresses. The C-More will request whatever data it needs to refresh the displayed screen. If a single screen includes a mixture of X, Y, and V memory from all four PLCs, that is three Modbus commands per PLC times four PLCs. It could take an objectionably long time between updates from the X memory in the first PLC.
You will also need to be careful in configuring alarms. The C-More tries to read from the memory associated with alarms even when the alarm screen is not displayed. Use of alarms will increase the time between updates.
Created Date: May 18,2007
Created by: twbrock
Ok if I go with RS-485/Modbus can the C-more be in the middle of the daisy chain?
Will each slave PLC have to have a different set of memory locations to report to the C-More?
Can the slave PLC send information to the C-More?
Still Confused but thanks for the help
TWBrock
Created Date: May 18,2007
Created by: bcarlton
The PLCs do not SEND information to the display. What I mean by this is that each PLC waits for a request from the display for information then replies. Since the display initiates all communication it is considered the 'master '
The 'master ' distinguishes each 'slave ' PLC by means of a MODBUS address. From your point of view as the display programmer the information in each PLC is not just a memory location (V2000) but a MODBUS address PLUS the memory location. In the CMore you define each 'device ' with its network address. You can then have identical memory references in each device which are still separate because one will belong to (for example) DEV001 and the same memory reference but in DEV002.
The connection will have to be to port 2 on the DL06's since only they have a changeable network address. And yes the display can be in the physical middle of the network. Termination resistors will go on the actual physical ends.
Created Date: July 03,2007
Created by: rsaksena
Can the C-more micro panels be used as a slave device on an RS485 network. We need to have multiple C-more micro display panels connected on and RS485 network which already has a master controller.
Created Date: July 04,2007
Created by: Tech Guy
No. Almost all HMI panels including the Cmore line are designed as mastering devices. Only one mastering device is allowed on a serial network.
Created Date: May 15,2007
Created by: twbrock
Now I’m confused see post ‘New Network’
After reading many posts I have more questions than answers
If I use 4 D0-06’s and 1 C-More commutating over RS-485/Modbus can I monitor or report to the C-More from all PLC’s
Does multi drop mean daisy chain? Or can the multi-drop be a Y?
Do I have to make one of the 06’s the master and have it pole the others and store the information to output to the C-More?