use strict;
use utf8;
use warnings;
use Mojo::JSON qw|from_json|;
use bytes;
use MBclient;

sub new {
    ... .;
}   

sub _device_read {

    # $d as data
    # $mbc as ModBusControl
    # $r as response
    my ( $d, $mbc, $r ) = ( shift, MBclient->new(), undef );
    
    # parse device config
    $d->{regs} = from_json( $d->{regs} );
    
    # setup device attributes
    $mbc->host( $d->{ip} );
    $mbc->port( $d->{port} );
    $mbc->unit_id(0);    # by default.

    # for all specified registers
    foreach my $reg ( keys %{ $d->{regs}->{r} } ) {
        $r->{$reg} = _prettify_byte(

            # read data from device registers
            $mbc->read_input_registers(

                # converting text register address to hex
                hex($reg),

                # specify number of registers to read
                $d->{regs}->{r}->{$reg}
            )   
        );
    }
    return ($r);
}   

# converts from hex data to deximal
# recieve output from modbus sensors
sub _prettify_byte {

    # okay state of deal
    return (
        sprintf( '%.2f', unpack( 'f', pack( 's2', @{ $_[0] }[ 1, 0 ] ) ) ) )
      if ( $_[0] );
      
    #return error message
    return ( $c{_err_} );
}