RasPiComm Forum is online
Posted by on January 14, 2013
Our new website is online!
Have a look at www.amescon.com/forum.aspx and start discussing or asking questions about the RasPiComm extension board.
You can even win a RasPiComm if you vote on the forum:
1st place: A Raspberry Pi + RasPiComm + OLED Display
2nd place: A Raspberry Pi + RasPiComm
3rd-5th place: A RasPiComm
The winners of the contest will be announced on 01/27/2013.
Daniel Amesberger 
The winners of the contest will be announced on 01/27/201_3_, I assume 😉
Yeah, sure. I’m still so 2012 😉
I corrected the post, thanks!
Daniel,
I purchased a raspicom. I am now trying to get RS485 to work using the modbus protocol.
Do you have preferred modbus library that have working with the Raspicomm?
Thanks for a great board.
Gerrie
P.S. Is it possible to order through you if I need large quantities?
Gerrie
Hi Gerrie,
you can use the serial kernel driver we provide (take a look at our getting started section). You should then be able to use any library which can send out and receive data over a serial port (in this case /dev/ttyRPC0).
You can contact us directly (office@amescon.com) if you need larger quantities.
Daniel
Daniel,
Thanks for you quick reply. Just to help me understand this. Does your kernel driver then take care of the RTS signal when using the RS485?
I should then use /dev/ttyRPC0 as a vanilla serial without any concern of sending the RTS pull-up signal during modbus writes.
If it helps, I have been using the libmodbus library but on the pi there is a problem. I cannot use the RS485 mode since the ioctl on pi (raspbian wheezy) does not recognise the TIOCSRS485 command. (Strange, but I have no idea why.)
It sounds to me that I should use the RS232 mode because your driver takes care of the any RTS signal that you need to send the RS485 Driver chip. Correct?
Gerrie
Yes, you are correct. Our driver takes care of the direction signal, You should be able to just use the RS232 mode. When you are writing to /dev/ttyRPC0 the direction is automatically switched to “send” and returns to “receive” after finishing the send operation. No additional commands needed.