We need to read some values using modbus on WinNT. Where can we find some OCX control, free if possible.

Thanks

 

Search on www.cdrom.com or any other big archive site. A search on google for modbus will also get you there. I've seen one. but I don't do windows so I don't have the particulars.

regards

Curt W.

 

Claudio:
Check www.wintech.com they have a Modbus OCX Master and a Modbus OCX slave but it is not free .
Best Regards

Ing Hanoi Santos Hung
Dpto Sistemas Digitales 3
Instituto Central de Investigacion Digital
email : [email protected]

 

Check out Automated Solutions website for full Modbus connectivity products. The development kits are not free, but are reasonably priced and well supported, the distribution copy of the controls are runtime-free.

Fully functioning demos are available for download.

Regards, Mark
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Hi Claudio,
the modbus protocol is not very complicated to write for NT.
You can use the Readfile and WriteFile instructions to manage the serial port.
If the PC is master, you can use the mscom32.ocx under VB.
If the PC is slave, I recommend you to use VC and the WaitCommEvent() thread.
The sole problem you can have is the managing of line. You have to put high the RTS (or DTR) before writing and put it low just after writing.
(use Sleep(1) after writing and before put down the RTS ( or DTR)). If you choose a little more expensive converter (RS485), it will manage the
line, and you just have to write and read the serial port.
All the specifications of Modbus are available at www.modicon.com

I have tested a free modbus driver available on internet. I remember that I have found it with FREE MODBUS DRIVER keywords. The author was Ricardo Saat, but I don't have noticed the address.
J-F Portala
SoViLor company

 

Hi Guys,

try www.win-tech.com . The have some pretty neat stuff on Modbus.

Cheers

 

I have tested a free modbus driver available on internet. I remember that I have found it with FREE MODBUS DRIVER keywords. The author was Ricardo Saat, but I don't have noticed the address.
J-F Portala
SoViLor company

 

Hi Claudio,
the modbus protocol is not very complicated to write for NT. You can use the Readfile and WriteFile instructions to manage the serial port. If the PC is master, you can use the mscom32.ocx under VB. If the PC is slave, I recommend you to use VC and the WaitCommEvent() thread. The sole problem you can have is the managing of line. You have to put high the RTS (or DTR) before writing and put it low just after writing. (use Sleep(1) after writing and before put down the RTS ( or DTR)). If you choose a little more expensive converter (RS485), it will manage the line, and you just have to write and read the serial port. All the specifications of Modbus are available at www.modicon.com

I have tested a free modbus driver available on internet. I remember that I have found it with FREE MODBUS DRIVER keywords. The author was Ricardo Saat, but I don't have noticed the address. J-F Portala SoViLor company