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.