How to read from HMI?

[nanocycle]

Hi every body,

Is it possible to connect a HMI(color touch panel) to avr and read data from it and send some parameters via avr to HMI?


regards,

[micropar]

Hi nanocycle,

Yes, you can read / write HMI with MODBUS. Most HMIs provides MODBUS compatibility. But you are required to use external PC based Program to build screen interface and download the same to HMI, which are available from maker of HMI, when you buy from them. Then you can connect with AVR having MODBUS firmware that you need to write yourself.

Regards,
--micropar--

[nanocycle]

Hi

Thanks so much for your reply.
But here there is one problem.Suppose that i made screens in HMI.and i want to read status of one button in the second screen.
What is the the data the will be send to HMI and what is the answer?Can you give me a example?
Also I don't know anything about MODBUS.As far as i know,avr is just only has RXD and TXD in TTL logic.
How we are able to change this logic to MODBUS.

Regards,

[patoliyarj]

MODBUS is different in the sense of protocol...
you should have to configure your HMI for the same and have to prepare your controller for rx and tx data on modbus. Also, many HMI having serial, rs485, Ethernet and even USB interface options...get the best suite to your application and controller and go ahead....

[samir]

Hi

Thanks so much for your reply.
But here there is one problem.Suppose that i made screens in HMI.and i want to read status of one button in the second screen.
What is the the data the will be send to HMI and what is the answer?Can you give me a example?
Also I don't know anything about MODBUS.As far as i know,avr is just only has RXD and TXD in TTL logic.
How we are able to change this logic to MODBUS.

Regards,

In ModBUS one configure each configure each Control variable(e.g Button) to user defined memory address in HMI.To read Status from salve Node you specify that address and command( Read Or Write in Modbus) in modbus Packet.Free moodbus stack is available at
http://www.freemodbus.org/index.php?idx=2
Regarding hardware,If your HMI has RS232 Support than MAX232 will do,for RS485 one have to use MAX485.and if Your HMI has ethernet port than have to use Network Interface Controller(NIC) like
ENC28J60 and require MODBUS over Ethernet Protocol
Hope this will help

[nanocycle]

I can no find any complete project in the net.
Do somebody knows any project with source codes?

regards