Danfoss VLT HVAC Series, Руководство по программированию, Страница: 259 / 338

24-11 Bypass Delay Time
Range: Function:
0 s* [0 - 600 s] Programmable in 1 s increments. Once the bypass function is activated in accordance with the
setting in par.24-10
Bypass Function
, the bypass delay timer begins to operate. If the adjustable
frequency drive has been set for a number of restart attempts, the timer will continue to run while
the adjustable frequency drive tries to restart. If the motor restarts within the time period of the
bypass delay timer, then the timer is reset.
If the motor fails to restart at the end of the bypass delay time, the drive bypass relay will be
activated, which will have been programmed for Bypass in par.5-40
Function Relay
. If a [Relay
Delay] has also been programmed in par.5-41
On Delay, Relay
, [Relay] or par.5-42
Off Delay, Re-
lay
, [Relay], then this time must also elapse before the relay action is performed.
Where no restart attempts are programmed, the timer will run for the delay period set in this pa-
rameter and will then activate the drive bypass relay, which will have been programmed for Bypass
in par.5-40
Function Relay , Function Relay. If a relay delay has also been programmed in par.
5-41 On Delay, Relay , On Delay, Relay or par.5-42 Off Delay, Relay , [Relay], then this time must
also elapse before the relay action is performed.
3.23 Main Menu - Cascade Controller - Group 25
3.23.1 25-** Cascade Controller
Parameters for configuring the basic cascade controller for sequence control of multiple pumps. For a more application oriented description and wiring
examples, see section
Application Examples, Basic Cascade Controller .
To configure the cascade controller to the actual system and the desired control strategy, it is recommended to follow the below sequence, starting with
par. 25-0*
System Settings
and next par. 25-5*
Alternation Settings
. These parameter can normally be set in advance.
Parameters in 25-2*
Bandwidth Settings
and 25-4*
Staging settings
, will often be dependent on the dynamic of the system and final adjustment to be
done at the commissioning of the plant.
NOTE!
The cascade controller is supposed to operate in closed-loop controlled by the built-in PI controller (closed-loop selected in Configuration
Mode , par.1-00 Configuration Mode ). If Open-loop is selected in par.1-00 Configuration Mode , all fixed speed pumps will be destaged,
but the variable speed pump will still be controlled by the adjustable frequency drive, now as an open-loop configuration:
VLT ® HVAC Drive Programming Guide 3 Parameter Description
MG.11.C6.22 - VLT ® is a registered Danfoss trademark
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