modbus domotic

ralph79 · Joined: 29 Aug 2007 Posts: 87

hi all,
I have been trying to make a small modbus protocol with one master and several slaves to make a residential home domotic system. But the main issue is that I have to inquire each slave from time to time (around 100/150ms) to know if they have an new order...that is why I rather prefer to have a different approach, eventually and modbus ethernet (so that each slave could acknowledge directly the master, but I don't have the source code for that, is there any one that has it? By the way, is there any other option to accomplish that? I will have one master and around 20/25 slaves... (push buttons and/or outputs)...
Thanks in advance.

Ttelmah · Joined: 11 Mar 2010 Posts: 19433

That is Modbus TCP/IP. Drivers with the compiler.
How old is your compiler?. The basic modbus 'layer' has been with the
compiler for ages, but the TCP drivers needed were updated a while ago.

You would probably need to talk to CCS. There are a number of examples
for the ModBus TCP, that they can supply separately.

Be 'aware', this is quite a bulky/complex driver, compared to the standard
serial Modbus implementation, and you are going to be adding
Ethernet hardware to each board.

ralph79 · Joined: 29 Aug 2007 Posts: 87

My compiler has several months... But somehow I don't have the tcp/ip drivers... But for my system I need somehow a solution similar to the tcp/ip modbus... The idea is to have communication only when is needed ( when you press a button for instance), to reduce at most the power consumption... It is not interesting (IMHO) to have domotic and spend a lot of energy to control the system...

ralph79 · Joined: 29 Aug 2007 Posts: 87

Is there any other system/protocol to accomplish this?! The idea is to control my house spending the less energy possible... Just for record, I will use bistable relays..and optocoupler entrys...

temtronic · Posted: Sat May 23, 2020 4:17 pm

There are several 'systems' that can be used, RS485 is a popular one. Which depends upon amount of data,'points' or slaves, and speed you require. Everyone has their 'favourite'. For a wired system, I still like what I used 30+ years ago, not fast at 24 baud but 99.999999% hackerproof AND can still communicate if a wire is cut or shorted.

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

ralph79 · Joined: 29 Aug 2007 Posts: 87

Hi temtronic,

When I thought in the "system" I think immediately in the modbus protocol (stable, with several nodes, good baud rates, etc) but when I come in the developing.. I somehow saw that is not good option (besides de tcp/ip module), it is not good programming inquire each 50ms all the 40/60 slaves checking if a push button was pressed... A and according to that send the data to the other 20/30 slaves for toggling one output... It's a spending a lot of energy for nothing... So i rather prefer to use a system that could trigger directly the master when it is needed... The bau rate I would like to use is something thing like 9600bps...

ralph79 · Joined: 29 Aug 2007 Posts: 87

hi PCM,
I have two versions (5.089) for the newer chips, and an ancient one: 4.140...in the recent one I have the following files:

Ttelmah · Joined: 11 Mar 2010 Posts: 19433

As I said, you have to ask CCS for the examples. They do supply them with
one of their development kits, but have been friendly in the past and
let other users have them.

ralph79 · Joined: 29 Aug 2007 Posts: 87

Hi Ttelmah,
I have asked for the examples to CCS, untill now, I didn't receive any info.. I will wait a couple of more hours/days...

newguy · Joined: 24 Jun 2004 Posts: 1904

ralph79 · Joined: 29 Aug 2007 Posts: 87

Hi newguy,
In fact I have received the feedback from CCS yesterday. Thanks in advance.