Created Date: September 24,2010

Created by: jackson

I am a little confused...

You are talking about serial Modbus in one part of your discussion and Modbus TCP in the other.

Which are you doing? Modbus RTU or Modbus TCP?

Have you tried getting any captures (serial from analyzer or Wireshark Ethernet) to show the data going back and forth?

If so, can you post this data here for us to see?

Which data locations are you trying to reach? Do you have the Modbus addresses mapped in P3000?

We need a lot more data if we are going to be able to help you.

Created Date: September 24,2010

Created by: JB_Tron

ModbusRTU now

Thanks for the response.

I had been using the NI forum and I neglected to start a thread here.

Here is the link to the NI forum;

http://forums.ni.com/t5/Lookout/Productivity-3000-modbus-communication-problem/td-p/1225836

I started with ModbusTCP but I gave up on that problem.

I prefer to use a dedicated serial link anyway.

Yes, I had mapped some P3 channels to modbus numbers.

I am giving up on this processor for now as I have spent way too much time and money trying to get it to work with a modern version of Lookout. I will have a bill from a consultant friend of mine that actually got the serial working using the modbusslave driver in Lookout. He had to put read/write rungs in the P3 logic and use remote URL's in Lookout.

Thanks anyway.

John B

Created Date: September 25,2010

Created by: dnj

The tag you are requesting out of the PAC is an analog value, this is a signed int 32 tag data type. Per your NI link, you were trying to request Modbus1.30001, this would only request one address (16 bit). I believe you would need to request Modbus.D30001, this request a double word register (32 bit). This could of been the source of the problem. In the Lookout help file should give you the data members allowed to be entered for using the Modbus driver, this is where I found the reference for adding the 'd ' to the address.

Created Date: September 26,2010

Created by: JB_Tron

Faulty processor

Go figure.

I have spent dozens of hours and $700 in consulting trying to make this processor communicate.

I was ready to box this system up and send it back when I borrowed another processor from a colleague and it works fine.

It took me ten minutes to set it up with a test program and it worked as expected.

I have a signal generator on an analog input that I mapped to 30001.

I put an expression in Lookout for "modbus1.30001 " and there it is.

A Lookout switch connected to ladder contact hooked to an output works instantaneously.

Since this processor has sub-millisecond scan time I was hoping to get the poll rate down to 1ms but the smallest poll rate I can specify in Lookout is 0:00.01 which is 10ms. I get good representation of a .1HZ signal but not 1HZ.

However, the poll rate seems to be 100ms as I see that there is no difference in a hypertrend trace between 0:00.1 and 0:00.01.

I am not sure what the bottleneck is as I have the baud set to 115.2K.

I will cancel the RMA's for this test system and just send back the DEFECTIVE processor.

I am really excited to implement this new hardware.

Onward through the fog.

John B

Created Date: September 23,2010

Created by: JB_Tron

Hello,

I have a Productivity 3000 system I am testing.

I have done dozens of jobs using NI Lookout and DL205 processors.

I like to use the serial link and dedicated PC for the HMI/SCADA.

This provides fastest communication thus giving the best chart recorder traces (hypertrend).

I have the most current version of Lookout 6.5 from NI.

The serial link does not work.

I get the "red X " on my test channels in Lookout.

The alarm I have in Lookout is;

"Garbled communication response from Modbus secondary(9):Incorrect secondary response "

The PC is set to com9 and the Modbus serial driver in Lookout is set to com9 and the link parameters match.

AD tech support tested the P3-550 with the old Lookout version 4.5 and said it works fine. They don't support current Lookout versions and won't test with it.

NI tech believes the problem is with the the P3 with regard to my first issues using modbusTCP. I just tried changing the serial port "receive gap " in Lookout from default 20 to 100 as per NI suggestion but that did not work. I am sending a serial log to Ryan at NI now.

Any suggestions would be greatly appreciated.

John B