perlquestion
PaulNg
<p>Latest update: Hi all, It's not the negative values that is throwing it off, rather the ff (Ascii chr 255) that the Telnet.pm can't seem to send! Can anyone advise me how can I do this? Thanks</p>
<p>Hi all,</p>
<p>I'm having problems with Telnet.pm and negative values. For some unknown reason, the reply in the buffer seems to be dropping characters, even a send doesn't seem to be sending correctly as the value on the controller did not respond. However, using a simulator, the value seems to have been sent correctly. Does anyone know why? All help is greatly appreciated. The controller I'm connected to is a WATLOW F4.</p>
<code>---MODBUS Packet details---
Slave address: 1
Read Write: 6
Start Address 1: 01
Start Address 2: 2c
Value 1: ff
Value 2: 9b
CRC 1: 73
CRC 2: 164
ASCII characters sent: !,ÿI¤!
Buff data: !,I¤!</code>
<code>
$data = join('',@buffor); #Modbus frame to scalar
# chomp($data);
print "ASCII characters sent: !$data!\n";
if ($Telnet) {
$pass=$ob->print($data)
or warn "Modbus client : problem with send: $!\n";
} else {
$pass=$ob->write($data)
or warn "Modbus client : problem with send: $!\n";
}
if ($Telnet) {
# Telnet
$TimeOut = int($TimeOut / 1000); # Convert to seconds
$ob->errmode('return');
my $i = 0;
do {
$Buffer = $ob->get(TimeOut => 1);
print "Buff data: !$Buffer!\n";
if (defined($Buffer)) {
$i = 0;
$Reply .= $Buffer;
} else {
$i++;
}
} until ((! defined($Buffer) and $i >= $TimeOut) or length($Reply) >= 8);
</code>