To record cameras only when an alarm input is activated
Set the cameras that will be recorded on alarm input to record on Event only in the Record schedule
Create an Event rule with alarm input (recorder) for the trigger and set the input pin number(s) and set the Event action to Record/Go to preset
Make sure the Alarm input type is set to Normally open or closed depending on the input contact type
Disable motion detection event rule so that motion detection will not trigger camera recording
When the alarm input contact is made the camera(s) will record.
For older recorders using the older style GUI
Set the camera to record Event only
Set the NVR sensor detection to normally open - select the camera number.
An alarm output can be triggered also and set to continuous - the pins from this can then be connected back in to the alarm input and ground, holding the alarm input on until the reset pin is connected to ground.
This will allow a Normally Open button connected to the alarm input and ground to be pressed and recording will stay on until a Normally Open button connected to reset and ground is pressed - stopping recording.