Parameter debugging of parallel unit controller for cold storage | pressure hysteresis, rotation time, loading delay, fault locking
The parallel controller is the brain of a multi head unit. Improper parameter tuning can lead to frequent start stop, uneven load distribution, rotation failure, and oil return faults.
The main control signal adopts the return air pressure, setting the loading pressure and unloading pressure. The pressure return difference cannot be too small. If the return difference is too small, the machine head will frequently start and stop, causing a large impact.
Set the rotation duration for rotation operation, usually every 4-8 hours, to balance the running time of each machine head; When rotating, ensure a smooth transition and prohibit direct cutting of the machine.
Loading delay: When the pressure reaches the loading set value, delay for a period of time before starting the next machine head to avoid multiple machine heads starting simultaneously and impacting the power grid.
Fault locking parameter: When a single machine head triggers serious faults such as high pressure and oil pressure difference, the controller locks the machine head and does not retry repeatedly, while the other machine heads continue to operate.
The Xitelide parallel controller supports two modes: pressure priority and duration priority; Cold chain warehousing prioritizes pressure, while balanced maintenance prioritizes duration.
Many debugging personnel set the hysteresis too low, and when the pressure fluctuates slightly, they add and unload, causing the machine head to repeatedly start and stop, and the losses of the contactor and shaft seal to accelerate exponentially.
Low load anti idle logic: If a single machine head runs for a long time, the controller will forcibly start another machine head to run for a few minutes, drive the pipeline to return oil, and then switch back.
For foreign trade projects, the customer's power grid capacity is relatively small, and the loading delay needs to be extended. The starting current should be staggered to prevent power grid tripping.
After modifying the controller parameters, it is necessary to save the parameters, export backups, and restore the controller to factory after power failure. Parameter confusion can easily cause unit failure.
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FAQ
What is the main control signal for parallel units? Return air pressure.
How often is the rotation of the aircraft head usually done? 4-8 hours.
3. What are the consequences of too little pressure hysteresis? Frequent start stop of the machine head results in significant impact losses.
How to deal with serious malfunctions of the machine head controller? Locked and no longer restarted repeatedly.
5. Low load anti idle logic function? Forcefully activate the standby machine head to drive the return oil.
How to adjust the power grid capacity when it is small? Extend the loading delay and stagger the startup.
7. What must be done after parameter debugging? Backup and save parameters.
