rs485 rtu 8n2 LUMEL

[rosol1992@o2.pl]

Good Morning,

I want to connect my Termometer (LUMEL P19) to Labview. I use converter USB->RS485 LUMEL PD10. I downloaded library for modebus.

I am enclosing config of P19 and information about errors which I received.

If I use correct adress of P19 I take error which is showed in the first picture.

If I change adress I recive this information:

RTU Data Unit.lvclass:Read ADU Packet.vi:5030001 and it is error nr 56.

I am enclosing the simples program which I wrote.

What didn't I do correct? What should I do for improving my program?

Thank you,

Krystian Rosłon

[KStachon]

Hello. 

We tried to resolve the issue with rosol1992. Finally, we investigated that parity control must be set properly: to none, instead of even. To do this, we must set desired value to "parity" terminal in "Create Modbus Instance" VI. 
Required MODBUS settings can be usually found in manual, enclosed to device we want to use. 

I'd like to list you few topics related to MODBUS communication in LabVIEW:

- Modbus libaries available in LabVIEW: https://decibel.ni.com/content/docs/DOC-30140
- MODBUS protocol basics: http://www.ni.com/white-paper/7675/en/

Regards, 

Krzysztof S.

[Wayne.C]

Common error in Modbus drivers.  1 stop bit if parity is used.  2 stop bits if no parity is used.  Must have a constant number of bits in data packet.