Issue
When using an MNL controller to accumulate a usage total, the output appears to reset when the pulse rate gets too low.
Environment
MNL family of controllers
Cause
As designed, if the pulse rate is too low, the output goes to zero.
The Pulse Counter function of the Binary Input object is designed to calculate a pulse rate value and a total pulse count value. Due to mathematical restraints within the processor of the controller, if the interval between pulses is too low, the pulse rate output goes to zero.
Resolution
The standard Lon controllers (MNL-50, 100, 110, 130, 150, 200, VAV) handle pulse rates down to a minimum pulse rate of 1 pulse per minute. If the pulse rate falls below one pulse per minute, i.e., less than one OFF to ON transition per minute, the pulse rate output will go to zero until the next pair of OFF to ON transitions that occur within one minute.
For the MNL-800 controller, the minimum pulse rate is one pulse every 4 minutes.
