Teltonika To Weintek - Modbus TCP

[Kidblue]

Hi,

Having fun at the moment trying to drag data out of a Teltonika modem (RUT950). I can pull the first register data value out ok but it fails when trying to read any other addresses.

have attached the Teltonika Modbus register table and two examples of the Weintek numeric data display properties. Address '4x_Double 1' reads the modem up-time (in seconds) absolutely fine, but any attempt to read the other registers causes a 'PLC No Response' error. I have tried several variations of the data type and driver parameters - still the same.

Any ideas?

Regards,

Rob

 

[AustralIan]

Try register 3.

MODBUS is supposed to be 16bit, so for your thirty two bit registers, you should be getting these at 1/3/5...

Some vendors forget to subtract 1 from the address before sending the request, so they would use address 0/2/4..., But doesn't seem to be the case here.

 

[AustralIan]

There are free or evaluation tools that you can set your computer as a master and slave to get the response you are after.
I think MOD R SIM is one, but can't recall the exact name.

 

[Kidblue]

Hi Ian,

Have actually tried all register addresses from 1 to 32 but all respond the same way with a failed error. I've also added a conversion on the HMI side to swap the words to get the format correct, and all this works fine - the 'modem up-time' value is accurate and reads correctly. It just doesn't seem to recognise anything above register 1.

Thanks.

Rob

 

[AustralIan]

Get both of them working with this, then see what the problem is.

http://www.plcsimulator.org/downloads

 

[danw]

I suspect that the so-called register numbering is in error. Values requiring 2 registers use successive/contiguous register numbers, so the next data value can not use a successive/contiguous register number

System Uptime, in Register 1, is a 32 long integer bit long integer, requiring 2 Modbus registers.
So GSM signal strength should start at register 3, not 2, because both registers 1 and 2 are used for System uptime.
Sys temp starting at register 5
Sys Host name starting at register 7
GSM op name starting at register 23, etc.
(all one-based registers values above. Zero based addresses would be 0, 2, 4, 6, 22

If the slave is 'smart' enough to recognize that a request for data that is incomplete, like either 1 register of a 2 register value or 1 register of a 16 register value, it might well reply with a Modbus exception code, that the master/client interprets as "PLC No response error".