NAME

Device::Modbus::Client - Modbus clients with Device::Modbus

SYNOPSIS

 my $r = $client->read_coils(
     address  => 23,
     quantity =>  6 );
 
 my $r = $client->read_discrete_inputs(
     address  => 55,
     quantity =>  7 );
 
 my $r = $client->read_holding_registers(
     address  => 1,
     quantity => 16 );

 my $r = $client->read_input_registers(
     address  => 6,
     quantity => 3 );

 my $r = $client->write_single_coil(
     address  => 33,
     value    => 1 );

 my $r = $client->write_single_register(
     address  => 33,
     value    => 3457 );

 my $r = $client->write_multiple_coils(
     address  => 64,
     values   => [1, 1, 0, 1] );

 my $r = $client->write_multiple_registers(
     address  => 64,
     values   => [345, 65, 67, 243] );

 my $r = $client->read_write_registers(
     read_address  => 14,
     read_quantity =>  3,
     write_address => 20,
     values        => [ 45, 87, 1, 298, 0, 0] );

 $client->send_request($r);
 my $adu = $client->receive_response;

 if ($adu->success) {
     $values = $adu->values;
 }

DESCRIPTION

This class implements Modbus clients. Clients must connect to servers, build requests, send them to the server, and receive their responses.

CLIENT METHODS

Requests that fetch information from a remote server

The following methods create request objects. They all receive the same arguments: an address and the quantity of bits or register to read. See the synopsis for examples.

read_coils

read_discrete_inputs

read_holding_registers

read_input_registers

Requests that send information to a remote server

The arguments for these methods are an address and a value or values. Again, see the synopsis:

write_single_coil

write_single_register

write_multiple_coils

write_multiple_registers

Request that reads and writes information from a remote server

This request receives two addresses (read and write), the quantity of records to read, and an array reference with the values to write:

read_write_registers

Other methods

Once you have one or more request objects, it is time to send them to the server:

send_request

This method receives a request object as its only argument.

receive_response

Finally, this method will return the response received from the server encapsulated into an ADU (Application Data Unit).

METHODS OF APPLICATION DATA UNITS

Responses from the server are returned to the client wrapped into an ADU object. The ADU has several methods to inspect the response and retrieve any requested information:

message

 my $resp = $adu->message;

Returns the actual response object.

function

 my $resp = $adu->function;

Returns the function name of the request and response objects.

code

 my $code = $adu->code;

Returns the function code of the request and response objects.

values

 my $values = $adu->values;

Returns an array reference with the values returned by the server. Valid only for reading requests.

success

 $val = $adu->values if $adu->success;

Returns a true value if the ADU contains a message and its function code is less than 0x80 (Modbus exception objects have a function code larger than 0x80).

SEE ALSO

Client methods to actually connect and close the connection to the server are available in Device::Modbus::RTU::Client and Device::Modbus::TCP::Client.

AUTHOR

Julio Fraire, <julio.fraire@gmail.com>

COPYRIGHT AND LICENSE

Copyright (C) 2015 by Julio Fraire This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.14.2 or, at your option, any later version of Perl 5 you may have available.

cpanm Device::Modbus

perl -MCPAN -e shell
install Device::Modbus