Connecting Modicon m580 to SCADAPack

[Muhemmed]

I am trying to read SCADAPack 474 modbus register using Generic Modbus DTM but it does not connect to the device and ends up with this error:

No device found at the specified address. All online functions are  disabled.

Has any one connected to SCADAPack to read the data so far? I would like to know if it is possible to read via DTM browser or we should use function blocks such as data exchange?

As such, what type of modbus address should we use in the SCADAPack, 5-digit or 6-gigit addressing?

Thanks

[Joel_Weder]

Hi Mohammad,

As a starting point the Modbus station number (device ID or address) configured in the SCADAPack must match the address specified in the M580 polling configuration. Also, if using Modbus TCP or UDP then the IP address and port number of the RTU must also match what is specified in the M580 polling configuration. 

The SCADAPack 474 by default will use 5-digit Modbus addressing, though it can be configured to use 6-digit if necessary.

I have not worked with the M580, and have only done a small amount of work with the M340. But when I created a program to poll a SCADAPack from the M340, I used a READ_VAR function block. See Test Scenario 2, starting on page 43 of the attached document. There is much more information in that document, some of which might be useful. Some (eg the Trio radio material) you can likely ignore.

If this is not sufficient to get you going, you may contact our Technical Support team for further guidance.  Open the web page below, then select the appropriate country.

https://www.se.com/ww/en/work/support/country-selector/contact-us.jsp

[BevanWeiss]

5 digit addressing is the most common, so I'd stick with this.  But that's really just about how the register is displayed, and not about the actual communications differences.

If you're using a DTM, then you're in the M580 and trying to read FROM the SCADAPack 474.  This is not the most common way, normally the SCADAPack would do the reading/writing from/to the PLC.  Since SCADAPacks have a quite powerful Modbus configuration engine... whilst the M340/M580 Modbus implementations are quite anaemic.

You will need to enable the ModbusTCP server on the SCADAPack.  And ensure that it has a valid Unit ID.  You will also need to ensure that you have configured a suitable number of Objects and given them appropriate contiguous modbus addresses to match that requested from the M580.  Since the M580 DTM can ONLY access Holding Registers, then ALL of your configured SCADAPack Objects should be 4xxxx holding registers.  and they MUST be contiguous.  You can have NO gaps in the address range that your M580 will be requesting.

In the M580 DTM you will need to make sure that IP address matches the SCADAPack, and that the Unit ID matches what you configured for the SCADAPack.

[Muhemmed · Accepted solution]

Hi Joel,

Thank you for your response. I used DTM in M580 and could read from and write to Holding Register of SCADAPack 474. 

Therefore, I confirm that it is possible to read and write by I/O Scanner and this might be also useful for others who want to communicate with SCADAPack from PLC.

Kind regards,

[BevanWeiss]

If it was Joel's answer that solved the problem for you, please mark Joel's answer as the solution, and not your own 'thank you' message.