View Full Version : RS-485 communication with Carel Mastercella

06-09-2012, 09:45 AM

For our products we are using Mastercella MD33 type digital controller units. These have RS-485 connection available on them, and you have to install an extra miniature card to enable it. Even we have the card installed, we cannot communicate with the device over RS-485.

I don't want to invest in a PCo PLC since the local distributor does not want to sell them without software, since they are producing software for the market, and I guess they don't want competition.

Also according to the manual, you just connect the cables and the RS-485 port on the device handles polarity by itself which causes a major frustration for me. Has anyone been able to communicate with these devices before just using a RS-485 converter or by other means? If you did, how?

06-09-2012, 05:41 PM
try these:
http://www.actrol.com.au/install/IR33UserManual.pdf page 17
we have connected directly before no problem ,check your registers,and address .
good luck

14-02-2013, 03:31 PM
the reason you are not getting any communication is :
H0 serial address needs to be changed on each and avoid two units with same serial address, you need to save the parameters so when you change H0 press on Prg and hold it in for 5 seconds to save it.

polarity is extremely important make sure +,_,GND is in the same order in your network.

and what type of front end, monitoring system you are using on site.


09-04-2013, 02:26 AM
Standard Carel Mastercella use "Carel protocol" at a baud rate of 19200.

Typically if you require modbus, the model number is different. The baud rate remains the same.

What are you connecting to??

14-04-2013, 01:32 PM
Behzad, good post ;)

install monkey
14-04-2013, 03:54 PM
pity it was 5 mths later from the original post!!:D