controlnet terminator fault

[mel_w]

Hi All
I have a controllogix controlnet network using just 1 remote io connection (1769-ACN) the cable is fairly short less then 3 M when I plug the terminator into the T tap at 1 end the network stops working and the network card errors
when I unplug the terminator then the network is fine is it ok to use the network with no terminators ? or does any one know a cause of this problem
Regards
Mel

 

[Ken Roach]

You should have two T-taps: one at the ControlLogix 1756-CNB module, and one at the adapter module.

Each of these T-taps should have a ControlNet terminator attached.

Are you sure this is a 75 ohm ControlNet terminator ?

Are you using Allen-Bradley 1786-series T-taps ?

What exactly is the remote adapter ? There is no such thing as a 1769-ACN for Compact I/O, though the 1794-ACN15 is a popular FLEX I/O adapter.

 

[mel_w]

Hi Ken
Thanks for your reply
The adapter is as you say a 1794acn all the parts are genuine Allen Bradley
The 1794 module was supplied by customers supplier who reckoned it would work with only 1 t tap and terminator because it was a short cable
(I have worked with Devicenet but mostly Siemens networks and is my
1st time with controllnet)
But with only 1 tap fitted at the cnb end the network crashes when the terminator is fitted
So if I fit a tap and terminator at the other end then it should work OK
Regards
Mel

 

[Operaghost]

Each device MUST have its own Tap. The length of the cable makes no difference.

OG