Zener 8000 Application Manual page 14

Application SW08020: Pump PID 2 [Advanced Pump PID Control]
Implementing 'Idle mode'
What is Idle Mode ?
Idle mode is a feature that automatically switches the pump off when a 'no flow' condition is detected. The
pump will then restart based on pressure ('% below SV') or PID output ('output frequency').
There are 2 methods in which the 'Idle Mode' can be configured.
1. "LOAD %" [DEFAULT] Monitoring the 'load %' to indicate when the pump load represents a no flow
situation. Idle mode is triggered when the load drops to the preset level for the preset time.
Depending on the pump performance and operating conditions a flow switch may be required. Eg.
Multiple set points.
2. FLOW SWITCH [DEFAULT] Connect an external flow switch that triggers 'idle mode' when no flow for
the preset 'idle delay'. The switch is connected to digital input on the option board D3(35). The default
setting requires a contact that opens on 'no flow'. This input is always active so a link is required when
a flow switch is not fitted. A flow switch is the best method to use when operated with a variable or
multiple set point. The flow switch provides a more simple setup process as the 'load % threshold' is
not used.
3. OTHER [CUSTOM] Use an internal logic function or other external device to trigger idle mode.
NOTE: Both the 'load %' and the 'flow switch' methods can be used simultaneously, with the same 'idle delay'.
Idle based on ' % Load'
This is detected by a drop in 'Load%' for a set period of time. For this to operate it is important to find the %
load under a 'No Flow' or 'Dead head' condition. Pumping will resume when the pressure falls below a
specified % below the Set point. A flow switch can also be installed to trigger the idle mode.
H100 IDLE %LOAD
H101 IDLE DELAY
IDLE:
%Load decreases with reduced flow to a level for a
period of time 'Idle Delay' and then goes into 'Idle
Mode' (sleep). Or ; The input from the optional
Flow Switch indicating 'No Flow' for the 'Idle Delay'.
To ensure correct operation the 'Idle' function must be checked and configured for all possible conditions.
For installations where multiple or variable set points the load% method may not operate under all
conditions and require a flow switch to be installed.
Page 13 Document: IM00127 RevB
H104 RESUME AT
PV threshold
18/04/18
PV feedback
time
ZENER 8000 is idle
WAKE:
When the pressure drops due to returned
demand the ZENER 8000 wakes automatically
and operates in PID mode.
Output Speed
%Load
PV feedback