I must confess, I'm somewhat mystified how this could work at all (unless you are leaving out an awful lot of details.)

Net::Telnet communicates using sockets in TCP over ethernet. The Watlow F4 only has RS232 or RS485 support built in. Are you communicating through a protocol converter? Or to a Modbus Master controller which is doing pass-through to the F4? Or something else?

Net::Telnet doesn't seem like such a great choice anyway for Modbus TCP. Telnet is generally geared toward ASCII (not absolutely, but in general,) and Modbus deals with raw, byte encoded hexadecimal strings. It probably isn't impossible to make it work, but it seems less than ideal.

Anyway, for anyone to give you better help, you are going to need to supply more detail about exactly what you are trying to do, what you expect to get, and what you are actually getting.

In reply to Re: Telnet.pm and Negative Values for Modbus by thundergnat
in thread Telnet.pm and Negative Values for Modbus by PaulNg

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