Communication problem with Modbus object in Lookout 3.8

[Dan992]

What means the error code 06 besides the following alarm message NO COMMUNICATION RESPONSE FROM MODBUS SECONDARY ? Lookout runtime-express version 3.8 build 7

[Patrick R.]

Greetings,
The alarm message "No Communication response from modbus secondary" means that communication cannot be established between the modbus object and your external device. Verify that you have set up the serial port settings properly and that you have configured the modbus object. Verify that your external device is functioning properly and connected to the PC. If all of these things are ok, you may need to increase the receive gap of the serial port settings and the receive timeout of the modbus object. There is a tutorial on the web which outlines the troubleshooting steps for communication in Lookout.

http://zone.ni.com/devzone/conceptd.nsf/webmain/033CD84BAC7E1E7586256A3300756284?opendocument

I hope this information is helpful. Have a good day!


Patrick R.

[iwon1once]

I have a similar setup using modbus that works fine with windows 98 & ME, however am having this same problem with windows xp. It did work o.k. until a Windows update (dont know which one) but now comes up with comms errors. I get about 5% valid responses. I was able to make it marginally better by adjusting the "Read holding Registers" in the advanced settings to 20 but it is still not acceptable. The same process file works fine with Win 98/ME. Does anyone else have any suggestions?

[Mike@DTSI]

On some of our systems we have to adjust serial port byte lengths and other settings.

Test some more 🙂
Mike

[Mike@DTSI]

Sorry, Receive Gap

[iwon1once]

Hi again. Have tried all sorts of variations on the serial port settings to no avail. I have managed to get my process working on one of two WinXP machines by deleting the lst and lks files and loading the process again. You have to go thru and reset your setpoints again after doing this. The other XP machine (the one I really want it running on) still has me stumped. Hope this works for you. Regards, Bruce