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Help with PLC5 to MCM3100 to OMNI Flow computers
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lawebster
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Wednesday 03 January 2007 12:14:03 pm |
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Help with PLC5 to MCM3100 to OMNI Flow computers
I have been tasked with using an existing PLC5/MCM3100 application to talk to a bank of Omni flow computers. We have two 3100s one of which has an open port 1.
I have read the user manual numerous times and have looked at the sample ladder code along with our existing code which was done by someone else.
My assumptions:
set up the MCM port 1 as the Master and the individual Omnis as Slaves each with a different address and connect via an RS-485 network.
How do I tell the MCM to poll each address? Is this done in the Command list, BTW Block IDs 80-99? Will each command only poll one register in the addressed Omni? In other words will Block ID 80 Command 1 poll register for flow, Command 2 poll register for pressure, etc?
Any nudges would be appreciated.
Thanks
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jsanders
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Wednesday 03 January 2007 4:04:59 pm |
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RE:Help with PLC5 to MCM3100 to OMNI Flow computers
The latest version of the User Manual is available from the 3100-MCM product web page at the following link:
http://prosoft-technology.com/content/view/full/1120
In the upper-righthand corner of that page, you will see a link to download the Manual.
If you look at Section 6.4, starting on page 46, you will see information on creating Modbus Commands to send out the port.
Basically, you can create up to 100 commands for the module to execute out of either port. Each command takes 10 words in a data table, even though not all ten words are used in each command. This means the 100 possible commands could take up to 1000 elements in N-type data tables. Since the module moves data in 50-word blocks, it will take up to 20 blocks to move the commands over to the 3100-MCM module. These will be moved when the Write Block IDs called for by the module are 80-99.
At the bottom of page 47, you will see the Command List Structure, showing how each Command Block holds 5 commands. The chart that follows on page 48-50 shows the structure of each command and the order of parameters in the command, explaining each parameter in detail. At the top of page 51, you will see a table listing sample commands as they might appear in a list created in the N7 table in ladder logic. N7:50-59 is the first command, N7:60-69 is the second, etc.
If you look at the "Port/Mode Select" description on the top of page 48, you will see that to configure a command to go out Port 1, you would use a value of 1, 5, or 9 as the very first parameter (N7:50, N7:60, etc. in the sample table on page 51.) Then, it's just a matter of completing the command list; setting the Command Block Count in the Configuration data table (N7:0-29 in our sample ladder logic is the Configuration table, word N7:22 would be the place for the Command Block Count) for the number of Command Blocks you wish to use (Number of Commands divided by 5, rounded up.)
If you require further assistance or have additional questions, please contact ProSoft Technical Support at 661-716-5100 or e-mail your request to:
Support@psft.com.
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lawebster
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Thursday 04 January 2007 12:53:43 pm |
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RE:Help with PLC5 to MCM3100 to OMNI Flow computers
Thanks for the help
On page 59, how do we know that Read Data is located in registers 0-99? or how do we set this parameter?
Also is the graphic wrong on page 28? and the wording on page 57 before 7.1?
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jsanders
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Friday 30 March 2007 4:16:52 pm |
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Moderated by Forum Administrator
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RE:Help with PLC5 to MCM3100 to OMNI Flow computers
The sample ladder, in the N7 configuration table,sets N7:20 to 4, declaring 4, 50-word Read Blocks and in N7:26 declares the first Read Block ID to 0. Block 0 is the lowest addresses in module memory, addresses 0- 49. Block 1 is addresses 50-99, etc. up to Block 79, the last User data block, addreses 3950-3999.
With this configuration, the module will transfer the 4 blocks from module memory addresses 0-199 as the 4, 50-word blocks, to the ladder logic. The logic has to be constructed to recognized each Read Block ID (0, 1, 2, & 3) and put the 50-words of data from that Input image into whereever the user program wants it to go...usually 200 consecutive elements of some N-table. The sample uses N10:0-199.
The graphic appears to be missing arrows that would show the flow into or out of Data Memory, Command List, and Config Memory. Otherwise, it is correct.
Other than the PLC/SLC reference and failing to mention that data may also be transferred from the module to the PLC, this information above the Section 7.1 heading is correct. The 3100-MCM, being of PLC5 planform will obviously not fit in an SLC chassis. This is apparently a left-over reference from when user information for the 3100-MCM for the PLC5 platform and 3150-MCM for the SLC platform were contained in the same manual.
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