5 Cascade Controller Features
5.1.1 Introduction
Once the cascade controller has been configured, it can be enabled or disabled through parameter 27-10 “Cascade Controller." To start the cascade
controller, the master drive needs to be started as a normal drive through the LCP or through field buss communications. It will then attempt to control
the system pressure by varying the speed of the adjustable frequency drive and by staging on and off pumps as needed.
Two stop functions are provided by the cascade controller. One function quickly stops the system. The other stages off pumps in a sequence, allowing
for a pressure controlled stop. For the VLT AQUA Drive equipped with safe stop, Terminal 37 will turn off all relays and coast the master drive. If any of
the digital inputs are set to [8] “Start” and the corresponding terminal is used to control the starting and stopping of the drive, setting the terminal to 0
volts will turn off all relays and coast the master drive. Pressing the OFF button on the LCP will cause a sequenced de-staging of all the running pumps.
5.2.1 Pump Status and Control
The 27-0* group of parameters provides a convenient place to check on the status of the cascade controller and to control individual pumps. In this
parameter group, it is possible to select a specific pump to view the current status, the current running hours, and the total lifetime hours. From the same
location, an individual pump can be manually controlled for maintenance purposes.
The parameter group is organized as follows:
Pump 1
Pump 2
Pump 3
Pump …
27-01 Status
On Drive
Ready
Offline-off
27-02 Control
No Operation
No Operation
No Operation
27-03 Current Hrs
650
667
400
27-04 Lifetime Hrs
52673
29345
30102
Navigate to the 27-0* group on the LCP.
Use the right and left arrows on the LCP to select the pump.
Use the up and down arrows on the LCP to select the parameter.
5.2.2 Manual Pump Control
The extended cascade controller allows for complete control of each pump in the system. Through parameter 27-02, pumps can be individually controlled
through their selected relays. A pump can be turned on or off outside of the control of the extended cascade controller, or can be forced to alternate the
lead.
This parameter is different than other value related parameters in that selecting one of these options will cause the action to occur and then the parameter
will revert back to its default state.
The choices are as follows:
•
No Operation - Default.
•
Online - Makes the pump available to the extended cascade controller.
•
Alternate On - Forces the selected pump to be the lead pump.
•
Offline-Off - Turns the pump off and makes it unavailable for cascading.
•
Offline-On - Turns the pump on and makes it unavailable for cascading.
•
Offline-Spin - Initiates a pump spin.
If any of the “Offline” selections are chosen, the pump will no longer be available to the cascade controller until “Online” is selected.
Extended and Advanced Cascade Controller
Option
5 Cascade Controller Features
MI.38.C2.22 - VLT
®
is a registered Danfoss trademark
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