Warning 34 won't hurt anything.
It usually comes up during startup, if the VFD has an communications option card (bacnet) and no communications connected.
After a couple of minutes without communications, you will get "Fieldbus Fault W34", a comm failure on the card.
It has no effect on the operation of the VFD, but if you want it to go away you can do one of 3 things:
1. Connect your bacnet comm (with some bacnet traffic).
2. Power off the vfd and remove the card, restart the drive. It will tell you that there has been an "option change", clear that alarm and you should be fine. This works if you are never going to use the card.
3. Change function 8-02 "control source" from Option A to "none". That way the vfd won't look for control comm from the card and the warning won't come up.
The intent of warning 34 is that if you lost communications on the card you could trigger certain events-- stop/full speed/preset speed-- things you might want to do if comm went down and you lost control of the VFD. Call us for more info you want to run a sequence like this.