How to talk with my RS485 Modbus devices

founder has asked for the wisdom of the Perl Monks concerning the following question:

I am just building a new house. I have to talk with my RS485 Modbus devices like BMS, inverter, heat pumps and air exchanger with heat recovery. I received in Control.com forum a first working answer, how to talk with my air exchanger with heat recovery from a terminal window under Linux Ubuntu:

dmesg | grep tty
modpoll -b 4800 -p none -a 1 -r 13 -c 1 /dev/ttyUSB0
modpoll -b 4800 -p none -a 1 -r 12 -c 1 /dev/ttyUSB0 10
[download]

After this worked, I installed Device::Modbus How to translate the above terminal commands into Perl using Device::Modbus?

Comment on How to talk with my RS485 Modbus devices Download Code

Replies are listed 'Best First'.
Re: How to talk with my RS485 Modbus devices by Anonymous Monk on Jul 18, 2021 at 09:40 UTC
try stuff? `modpoll -b 4800 # Baudrate -p none # No parity -a 1 # Slave address (1-255 for serial, 0-255 for TCP, 1 is d +efault -r 13 # Start reference (1-65536, 1 is default) -c 1 # Number of values to read (1-125, 1 is default), option +al for writ ing (use -c 1 to force FC5 or FC6) /dev/ttyUSB0` [download] so `my $client = Device::Modbus::RTU::Client->new( port => '/dev/ttyUSB0', baudrate => 4800, parity => 'none', ); my $req = $client->read_holding_registers( address => 1, # -r quantity => 1, #-c ); $client->send_request($req); my $resp = $client->receive_response;` [download] https://grep.metacpan.org/search?q=start&qd=Device-Modbus&qft= https://metacpan.org/release/JFRAIRE/Device-Modbus-RTU-0.022/source/examples/simple_client_rtu.pl	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re: How to talk with my RS485 Modbus devices
by Anonymous Monk on Jul 18, 2021 at 09:40 UTC

try stuff?

 
modpoll
-b 4800 #          Baudrate
-p none #          No parity
-a 1 #          Slave address (1-255 for serial, 0-255 for TCP, 1 is d
+efault

-r 13 #          Start reference (1-65536, 1 is default)
-c 1 #          Number of values to read (1-125, 1 is default), option
+al for writ
ing (use -c 1 to force FC5 or FC6)
/dev/ttyUSB0
[download]

my $client = Device::Modbus::RTU::Client->new(
    port     => '/dev/ttyUSB0',
    baudrate => 4800,
    parity   => 'none',
);
 
my $req = $client->read_holding_registers(
    address  => 1, # -r
    quantity => 1, #-c
);
 
$client->send_request($req);
my $resp = $client->receive_response;
[download]

https://grep.metacpan.org/search?q=start&qd=Device-Modbus&qft=

https://metacpan.org/release/JFRAIRE/Device-Modbus-RTU-0.022/source/examples/simple_client_rtu.pl

[reply]
[d/l]
[select]