OM WGS-5
WGS 130A to 190A
85
Increment = [(Error) * (Error Gain setpoint)] + [(Slope) * (Slope Gain setpoint)]
Where: Error = ECWT – Valve Setpoint
Slope = (Present CP) – (Previous CP)
When the Error is > the Valve Deadband setpoint, the valve position analog output (%
of full scale) is updated according to the following equation.
New %Position = Old %Po Increment/10
Valve Stage, controls from the fan stage setpoint in use. It is recommended that the
Valve Setpoint method explained above be used rather than this mode.
This mode is only operational when the Valve/VFD Control setpoint is set to Valve
Stage. In this mode the valve output is controlled as for Valve Setpoint mode (above),
except that the active setpoint for the controlled parameter is selected according to the
following table.
# Of Fans ON
Active Setpoint
0 Valve
Setpoint
1
Stage #1 ON
2
Stage #2 ON
3
Stage #3 ON
4
Stage #4 ON
VFD Stage, ValveSP/VFDStage, When the Valve/VFD Control setpoint is set to None,
Valve Setpoint, OR Valve Stage, this output is set to 0. Otherwise, it will be controlled
in a manner identical to Valve Stage Mode (above) except that (1) it shall be kept at zero
until the first fan stage is ON, and (2) the following setpoints do not apply.
Valve Control Range (Min)
Valve Control Range (Max)
Valve Type
Valve Type settings are NC (normally closed to tower) or NO (normally open).
These settings establish the operation of a tower bypass valve (must be a 3-way valve).
Initial Valve Position
When the condenser pump is not in the RUN state, the valve output shall be set as a
function of entering condenser water temperature (ECWT) per the following graph.
Figure 12, Initial Valve Position
Max Position @
Setpoint
(90°F)
Min Position @
(60°F)
Min Start Position
(10%)
Initial Valve Position
(values are examples only)
Max Start Position
(90%)
Setpoint
Setpoint
Setpoint
Summary of Contents for WGS130AA: WGS140AW
Page 97: ......
