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<p>Hi Everybody,
<p>I am writing a Modbus Client program using TCL/TK 8.4 I am having problems configuring the ports for half duplex communications.
<p>I open the (half duplex) port as
set comHandler [open //./COM$port r+]
and use filevent for reading the port whenever it becomes readable.<br>
fileevent $comHandler [list read $comHandler]
<p>I use vwait to enter eventloop processing
<pre>
while {1} {
vwait seqNumber
if {$seqNumber>$serialTest::FRAME_COUNT} {
break
}
}
</pre>
<p>But when I run my script I get error Error reading %comHandler Could anybody suggest how can I control my RS485 half Duplex communication Is there any need to look for Handshaking signals.
<p>Thank you very much in advance!!
<p>Dhillon
<p>I am writing a Modbus Client program using TCL/TK 8.4 I am having problems configuring the ports for half duplex communications.
<p>I open the (half duplex) port as
set comHandler [open //./COM$port r+]
and use filevent for reading the port whenever it becomes readable.<br>
fileevent $comHandler [list read $comHandler]
<p>I use vwait to enter eventloop processing
<pre>
while {1} {
vwait seqNumber
if {$seqNumber>$serialTest::FRAME_COUNT} {
break
}
}
</pre>
<p>But when I run my script I get error Error reading %comHandler Could anybody suggest how can I control my RS485 half Duplex communication Is there any need to look for Handshaking signals.
<p>Thank you very much in advance!!
<p>Dhillon