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Use the Windows utility 'telnet' to check if it will be possible for SpecView to connect to an instrument on a given IP address over TCP.

 

Note: On Windows 7 the ‘telnet’ client utility program is not available by default.

Administrator privileges will be required to enable it.

Go to the Windows Control Panel ‘Programs and Features’ to enable it. Click 'Turn Windows Features on or off' (on the panel on the left of this box).

When the list is displayed enable (tick) 'Telnet Client'.

 

This is an example of testing the connection to a an instrument at IP address: 192.168.1.64 using port 502:

 

First ensure that SpecView is NOT running because it is not possible to have both telnet and SpecView connected at the same time.

 

Open a 'Command Prompt' window, then enter: (Note that there is a just a space between the IP address and the '502' port number)

 telnet  192.168.1.64 502

 

If this gives an error then there is a problem with the network, in which case try:

 ping 192.168.1.64

 

The 'ping' utility just checks if an address exists (so it doesn't need the port number), whereas 'telnet' actually connects, which is more useful when troubleshooting.

 

If ‘ping’ works, but telnet doesn’t then possibly the instrument isn’t answering on port 502 (Port 502 is the default port for Modbus instruments over TCP) in which case check the port settings on the instrument.

 

If ‘telnet’ gives a blank screen with a flashing prompt, then it has connected successfully.

Press CTRL+] to get a ‘>’ prompt, then to close telnet type: quit

 

If telnet connected successfully, then once telnet has closed (it is not possible to have both telnet and SpecView connected at the same time) then SpecView should be able to connect. If not then please contact a SpecView representative.