I still cannot communicate via modbus

[labsys]

Reference#677685

Murali

I finally got back to the customer site to test the Lookout 5.1 Modbus file
and it still causes errors. What I cannot understand is why the Lookout 5.0
Demo works with this address and the Lookout 6.0 does not, even with all
the
fixes. I need to resolve this issue in the near future, my customer is
getting impatient, since I cannot fully communicate with his variable
drives.

Is there a way to make the Lookout 5.0 demo into a working copy. I know I
purchased Lookout 6.0, but it still is not giving results.

Tha address in question is 48193.2 trying to access bit level command for an Allen Bradley PowerFlex 40 Variable Drive. It works fine in the Lookout 5.0 demo but not with 6.0 even with the Modbus file of Lookout 5.1

Thanks for any help,

Ray Valdes
Labyrinth Systems, Inc.
2 Bert Drive, Suite 12
West Bridgewater, MA 02379

tel:   508-587-3060
fax:  508-587-0907

[erblock]

Hi Ray,

I use the modbus RTU via an Ethernet Serial Server COM port and RS-485 (2-wire) to several GE-Fuji VFD's.  No changes were required to run on Lookout 6.0.1+.  However, my setup is a little weird (testing Lookout 6 but can't commit until they fix lots of stuff) and in limbo right now, but it does function as described below!

I have a server machine and process that talks to the modbus devices, not directly, but through a Data-Table object.  I use broadcast (address 0) to send commands out to all drives at the same time (no response or validation of the command) through the data-table and I read back several status items from individual VFD's through the table also.  I also have a read only client process running on the same server machine for indication/status only.  The commands are actually sent out through a Lookout 5.1 remote client process that talks to the server machine, controlling the drives via the Lookout 6.01+ server process there.

I know this is confusing the point, but it seams with a data-table setup....Lookout 6.0.1 works fine...for me anyway.

Let me know if I can help with any specifics.

Ed

[erblock]

Gee-Whiz Ray,

I just realized you are only 1/2 hour from where I live (Plymouth) and I work in Cambridge.  I could arrange time to lend an on-site hand if that works for you.

Ed

[labsys]

The specific object I am having trouble with is communicating to an Allen Bradley Powerflex 4 drive. With Lookout 5.0 evaluation copy I was able to address memory location 48193.2 which is the start bit. With Lookout 6.01 the bit is not accessible and causes a communications error.

I cannot understand why this works under Lookout 5.0 eval but not under 6.0 I have repeatedly asked NI to just send me a copy of 5.0 even though I paid for a full version of 6.0 with no luck

The bottom line is that something that works well under 5.0 does not work under 6.0 or 6.01 and I cannot seem to convince them of this fact. I feel like a heretic back in the Dark Ages trying to convinve the church that the damned world is NOT flat.

[labsys]

Ed,

The site is in my new office in Marshfield (exit 12)

Lookout 5.0 Eval worked ok, but the 6.0 crashes and locks up with the identical command.

I believe that the way 6.0 handles the modbus.cbx file has an error. At times I get a read error when it should be trying to write and not read. 48193.2 is a write function when I edit the connection and is not a read point on the Allen Bradley Variable Drive

Ray

[erblock]

Are you using Ethernet or serial Modbus?

[labsys]

I am using Serial Modbus. The program I have worked well under 5.0 Demo, so I know the program is not the problem.

The problem is when I purchased and installed 6.0, the same addresses that worked under 5.0 worked great except for the one. NI does not believe me, they think I am doing something wrong, but they have no way to verify it. I tried to tell them I have been using Modbus with Lookout for several years with no problem, but they still insist that I am doing something wrong. They said they could not duplicate the error, but they also did not try to connect 6.0 to an Allen Bradley Drive.

The address that starts and stops the drive under Lookout 5.0 DOES NOT work under 6.0

[Khalid]

Please allow me to comment... The following quick test should reveal difference, if any, between the two versions:  create a simple process file with only a Write operation to the 48193.2 bit.  Run the process file in both 5.0 and 6.0 and log the communications to diagnostic files.

http://digital.ni.com/public.nsf/allkb/CAC576863FF648A186256B5900794761?OpenDocument&node=133080_US

If the Modbus messages are different then we have a problem with the Object. 

Regards,

-Khalid