adccommunitymod (AutomationDirect) asked a question.
Created Date: May 19,2006
Created By: sdsmith
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Hello, I have a potential customer that wishes to use a Modbus communication to extract information, and change values within V-memory locations from a AD controller. I have never dealt with Modbus before, so please be gentle. I have a number of questions, but to let you know, the controller/s will have 4 to 8 analog inputs (reading temperature), and 52 outputs. I am not sure if I plan to use one or two controllers. If I use two, I was thinking of use the DL06 or DL205s, if not a DL405. 1-To start with: what information should I obtain about his Modbus Protocol? 2-Which DL series would you suggest and are additional modules required? 3-If I use two controllers, and each has the “identical� programs within them, will they be able to distinguish between the two when gathering info and changing values? 4-I only wish for them to be able to look at certain T, CT, V-memory locations. If I place a password into the CPU, (starting with the letter “A�) will they be restricted from looking at the program or other values? I do this all the time when using LODirect and EZText displays, does the same hold true with Modbus? 5-Within my existing program, what extra code do I need to implement? 6-Should I or can I place this code at the end of the program? I would really appreciate any input or recommendations that all of you have. Thanks
Created Date: May 19,2006
Created by: bcarlton
1. www.modbus.org - this has the specs
2. DL06, DL250, DL260 - selected for RS422/485 available without additional cards.
3. Yes - you will set an individual 'address ' in the 'setup Secondary Comm Port ' dialog. The PC software will refer to that in its transmissions.
4. If the remote PC has access at all it can get at everything. It won't be able to get at the program though.
5. The remote PC is doing all the work. Besides setting up the comm port address, baud rate etc you don't have to do anything more. Be sure that the PLC and the remote PC aren't writing to the same location. You can get undefined results.
6. See #5
Created Date: May 19,2006
Created by: bcarlton
If you do go the MODBUS route the PC can't just ask for 'V2000 '. The AD registers have MODBUS equivalents but it's complex. At http://support.automationdirect.com/technotes.html pick up 'AN-MISC-009 ' and 'AN-MISC-010 ' for help.
Created Date: May 19,2006
Created by: sdsmith
bcarlton,
Many thanks for the quick reply. I'll check the info out.
Created Date: May 19,2006
Created by: sdsmith
Hello,
I have a potential customer that wishes to use a Modbus communication to extract information, and change values within V-memory locations from a AD controller. I have never dealt with Modbus before, so please be gentle. I have a number of questions, but to let you know, the controller/s will have 4 to 8 analog inputs (reading temperature), and 52 outputs. I am not sure if I plan to use one or two controllers. If I use two, I was thinking of use the DL06 or DL205s, if not a DL405.
1-To start with: what information should I obtain about his Modbus Protocol?
2-Which DL series would you suggest and are additional modules required?
3-If I use two controllers, and each has the "identical" programs within them, will they be able to distinguish between the two when gathering info and changing values?
4-I only wish for them to be able to look at certain T, CT, V-memory locations. If I place a password into the CPU, (starting with the letter "A") will they be restricted from looking at the program or other values? I do this all the time when using LODirect and EZText displays, does the same hold true with Modbus?
5-Within my existing program, what extra code do I need to implement?
6-Should I or can I place this code at the end of the program?
I would really appreciate any input or recommendations that all of you have.
Thanks