Operating Instructions

SED2 Operation & Maintenance Manual Addendum
186 Siemens Building Technologies, Inc.
Hibernation Mode
If the SED2 reaches the hibernation setpoint in PID operating mode, the P2391 hibernation
timer starts. After the timer expires, the SED2 drives the output frequency of the ramp to 0
Hz.
f
0%
T1 T2 T3 T4 T5
Output [Hz ]
P2392 Restart freq.
P2390 Hibernation freq.
Min. freq.
P2391
Hibernation timer
Hibernation
mode
Restart
Drive frequency
PID frequency
max.
hibernation
(-) error [%]
Time [s]
Time [s]
5192D06en
PID error [% ]
Figure 50. Hibernation Mode.
T1 Hibernation frequency reached.
Start of hibernation timer.
T2 Minimum output frequency reached.
T3 Output frequency decreased according to the set ramp.
PID control of the output frequency is interrupted.
T4 Output frequency = zero (motor standstill).
T3 to
T5
The PID fault signal [%] is monitored.
NOTES:
Observe polarity of the PID fault signal.
Polarity of the PID fault signal must match the sequence of the controlled functions
(cooling/heating or vice-versa).
The temperature setpoint can be below 0°C.
The PID fault signal can be positive or negative.
T5 SED2 output frequency is again increased.
PID control of the output frequency is again enabled.