ML1400 RTU Master To Dynagen Modbus issues

[gatfu]

I just tried even and odd. I also tried 1, 1.5, and 2 stop bits as well...still no good.

 

[gatfu]

I have never tried it but can i call allen bradley tech support or do i have to have a paid membership to access tech support?

 

[Ken Roach]

At this point you really need an oscilloscope to find out what the MicroLogix is putting on the RS485 line, so you can compare it to what ModScan32 puts on the RS485 line.

I've done many applications with the MicroLogix 1400 and it works really well as a Modbus RTU Master.

If possible, maybe try connecting the MicroLogix 1400 to the USB/RS485 device and test out ModSim32 as a slave device.

 

[bernie_carlton]

Or possibly set up the Micrologix as a Modbus slave and see if Modscan32 can read from it.

 

[gatfu]

Thanks guys for all the help on this one....I will give those last items a try and report back.

If all else fails I do happen to have a red lion dsp i can pull off the shelf and work around it that way i guess.

 

[gatfu]

Ok, So to follow up on this i tried both items mentioned above and neither one worked. While sitting there pondering what troubleshooting steps to take next it dawned on me that I have another machine in my shop that is down for maintenance and it has a ML1400. I figure why not try a complete controller swap out to verify is the 485 port is bad or not. The Problem followed. this tells me that the hardware is good and leads me back to thinking this may still be some config error on my end....although I have scoured over the settings countless time. I figure I ask one more time before I revert to Plan b and route all Modbus Comms To a Red lion DSP. Can anybody see anything wrong with my config or code with in my program or can anybody think of any thing else i might be able to try?

I want to say thanks to everybody in helping me with this issue as well...I love this forum and your help has always been greatly appreciate!!!!

 

[gatfu]

As a side note I have also opened a ticket up with dynagen directly to see if there are any known issues with ML1400 playing nice with Dynagen controllers. I have yet to hear back from them.

 

[diat150]

a few differences I see in my program that polls 3 or 4 different slaves

I have my inter char timeout set at 15ms and pre transmit delay set to 50 ms on the comm channel screen.

Another thing that I see is that in the message block, mine does not have the option for remote station address or remote bridge link id. Also, "local bridge addr" in yours is called Slave Node Address in mine.

I went ahead and copied and pasted my msg block out of my working project and it carried over like it should have. Go ahead and try it out and see if that makes a difference. I have a feeling the MSG block got hosed up somehow.You will see how mine looks different than yours did.

 

[gatfu]

Thanks diat150...I gave it a shot and it still times out. I am beginning to wonder if the dyna gen and ml1400 just don't like each other.

 

[diat150]

Thanks diat150...I gave it a shot and it still times out. I am beginning to wonder if the dyna gen and ml1400 just don't like each other.

that would be unusual. as long as you arent doing anything funny with your modbus test client to get it to come in I would think it should work. In my program I am talking to 3 different types of devices, and a total of 10 overall devices.

 

[gatfu]

Just an update on this problem....I have switched to my Plan B and it works just fine. I am now reading the MODBUS data with my Red Lion DSP and using the Protocol conversion tool to send the data via Ethernet to the ML1400. Its not Ideal, but then again this is only Genset Parameter Data...No Control.

Thanks again to everybody for helping me try to troubleshoot this anomaly....