McQuay MicroTech II User Manual

Page 68 OM 780-2
Propband position or VFD speed. Range = 1 – 99 psi (6 – 683 kPa). Default = ±10 psi (±69 kPa)
Loop Differential
Pressure Sample
Time
This value sets the “sampling period” used in the PID control function that modulates the loop differential pressure. In
general, increasing this value has a slowing effect and decreasing this value has a speeding effect on the control of the valve
position or VFD speed. When using a pump VFD, a typical sample time to start tuning the system is one second. When
using a loop bypass valve a typical sample time to start tuning the system is 15 seconds. Range = 1 – 60 seconds. Default
= 1 second
Loop Differential
Pressure Integral
Time
This value varies the “integral time” used in the PID control function that modulates the loop differential pressure. In
general, increasing this value has a slowing effect and decreasing this value has a speeding effect on the control of the valve
position or VFD speed. Range = none. Default = 120 seconds
Loop Differential
Pressure PI
Function Graph
A graph of the Differential Pressure vs. Time is shown at the bottom of the page when the Chilled Water Loop Modulation
Control Option = Chilled Water Loop Bypass Valve or Pump VFD to assist in tuning the PI loop.
Minimum Loop
Bypass Valve
Position
If the Pump Control Option = Sequencing and the Chilled Water Loop Modulation Control Option = Chilled Water Loop
Bypass Valve, the bypass valve must be less than this Minimum Loop Bypass Valve Position for a pump stage-up to occur.
Range = 0 to 100 %. Default = 20%
Maximum Loop
Bypass Valve
Position
If the Pump Control Option = Sequencing and the Chilled Water Loop Modulation Control Option = Chilled Water Loop
Bypass Valve, the bypass valve must be less than this Maximum Loop Bypass Valve Position for a pump stage-down to
occur. Range = 0 to 100 %. Default = 90%
Multiple VFD Controlled Pumps (if Pump Control Option = Multiple VFD Pumps, the following inputs are valid)
Name Description
Number of VFD
Controlled Pumps
This input defines the maximum number of VFD controlled pumps that the CSM will enable in order to satisfy the
cooling load’s demand for flow. Range = 2 to 6 pumps. Default = 2 pumps.
1
st
Pump Stage-Up %
2
nd
Pump Stage-Up %
3
rd
Pump Stage-Up %
4
th
Pump Stage-Up %
5
th
Pump Stage-Up %
If the Pump Control Option = Multiple VFD Pumps, stage-up from 1 pump enabled to 2 pumps enabled will not
occur until the Cooling Load Pump VFD Speed has been above the 1
st
Pump Stage-Up % for a continuous period
of time greater than the 1
st
Pump Stage-Up Delay Time. Stage-up from 2 pumps enabled to 3 pumps enabled
cannot occur until the Cooling Load Pump VFD Speed has been above the 2
nd
Pump Stage-Up % for a continuous
period of time greater than the 2
nd
Pump Stage-Up Delay Time, etc. Range = 0 to 100%. Default = 95%
1
st
Pump Stage-Up Delay
Time
2
nd
Pump Stage-Up Delay
Time
3
rd
Pump Stage-Up Delay
Time
4
th
Pump Stage-Up Delay
Time
5
th
Pump Stage-Up Delay
Time
If the Pump Control Option = Multiple VFD Pumps, stage-up from 1 pump enabled to 2 pumps enabled cannot
occur until the Cooling Load Pump VFD Speed has been above the 1
st
Pump Stage-Up % for a continuous period
of time greater than the 1
st
Pump Stage-Up Delay Time. Stage-up from 2 pumps enabled to 3 pumps enabled
cannot occur until the Cooling Load Pump VFD Speed has been above the 2
nd
Pump Stage-Up % for a continuous
period of time greater than the 2
nd
Pump Stage-Up Delay Time, etc. Range = 1 to 60 minutes. Default = 2 minutes
2
nd
Pump Stage-Down %
3
rd
Pump Stage-Down %
4
th
Pump Stage-Down %
5
th
Pump Stage-Down %
6
th
Pump Stage-Down %
If the Pump Control Option = Multiple VFD Pumps, stage-down from 2 pumps enabled to 1 pump enabled cannot
occur until the Cooling Load Pump VFD Speed has been below the 2
nd
Pump Stage-Down % for a continuous
period of time greater than the 2
nd
Pump Stage-Down Delay Time. Stage-down from 3 pumps enabled to 2 pumps
enabled cannot occur until the Cooling Load Pump VFD Speed has been below the 3
rd
Pump Stage-Down % for a
continuous period of time greater than the 3
rd
Pump Stage-Down Delay Time, etc. Range = 0 to 100 %. Default =
47.5%, 63%, 71%, 76%, 79% respectively
2
nd
Pump Stage-Down
Delay Time
3
rd
Pump Stage-Down
Delay Time
4
th
Pump Stage-Down
Delay Time
5
th
Pump Stage-Down
Delay Time
6
th
Pump Stage-Down
Delay Time
If the Pump Control Option = Multiple VFD Pumps, stage-down from 2 pumps enabled to 1 pump enabled cannot
occur until the Cooling Load Pump VFD Speed has been below the 2
nd
Pump Stage-Down % for a continuous
period of time greater than the 2
nd
Pump Stage-Down Delay Time. Stage-down from 3 pumps enabled to 2 pumps
enabled cannot occur until the Cooling Load Pump VFD Speed has been below the 3
rd
Pump Stage-Down % for a
continuous period of time greater than the 3
rd
Pump Stage-Down Delay Time, etc. Range = 1 to 60 minutes.
Default = 5 minutes

McQuay MicroTech II Specifications

General

Brand	McQuay
Model	MicroTech II
Category	Controller
Language	English