Modbus RTU

Modbus RTU

Hi
I have tested connect between Zenon with meter MK6E from EDMI and I have some problem.
The MK6E has meters registers are 32 bits the meter software will utilise 2 ModBus addresses. The Mk6 Genius meter accepts valid ModBus messages with function code 3- Read Holding Register. The register address ranges from 0001 to 9999 which corresponds to 40001 to 49999. Each register address represents a 16 bit word (2 bytes), so to read a float (4 bytes) requires 2 registers.
When a request is received the meter will translate that register address into an internal EDMI register. Each ModBus register address refers to a 16 bit word (2 bytes). When reading other data types, like floating point numbers that are 32 bits (4 bytes) wide, there is no standard. ModBus is big-endian, MSB transmitted first, but the 32 and 64 bit numbers are undefined. Most ModBus reading programs have a big-endian or little-endian option, although not all do. To cope with this, the meter also has a big-endian / little-endian option.
I use the neter to make modbus address to register map (Ex: 9071 to 40169). With the meter software I check the register value (see picture meter). With the modbus poll software, I poll the address 9070 get the right value (see picture modbus) (I tried on different time so the value see not match but it is correctly between software and meter).
I use zenon to connect with meter, but the Modbus driver only polling with address 9071, at the start-up runtime, the value received seem right , but the value do not update ( variable display spontaneous , global time in driver is 1000 ms..). Other register with type "Float" are worked fine.
Could you give me some suggestion?
Thanks.

This is a migrated post! Originally posted on 24.09.2011 by user skywalker. Please be aware that information can be outdated.

    Disclaimer

    This document governs the use of our Community Forum. By registering and using the platform, you accept these conditions.

    The COPA-DATA Community Forum serves to encourage the exchange of information and experience about the zenon software between forum users respectively zenon users.

    Please mind that any published information on the Community Forum is the subjective opinion and view based on the experience and the level of knowledge of the author. COPA-DATA does not overtake any responsibility for the content and the accuracy of the shared information.

    Users of the Community Forum are encouraged to share only well-founded experiences and to point out any risks associated with the implementation of proposed solutions to problems. COPA-DATA at its absolute discretion, reserves the right to moderate the forum. In this connection COPA-DATA may remove any information containing false facts, potentially dangerous solutions, bad language or content that may insult, degrade or discriminate others. COPA-DATA may block a non-complying user from forum access if the user violated this provision.

    COPA-DATA reserves the right to change this document from time to time at own discretion.


    Ing. Punzenberger COPA-DATA GmbH
    Karolingerstraße 7b · 5020 Salzburg · Austria
    www.copadata.com