Configuration
Configuring The Controller
Analog Output #1
In this example Analog Output #1 is configured for the “Tower Fan
VFD” output. In
Figure 33
Item #1 it indicates it has a Control Type of
“Direct Acting Floating Point”.
Item #2 indicates the Control Source for this relay will be the Tower Re-
turn Water Temperature (“TW Return”) on AIN2. Item #3 indicates that
the “Max Setpoint” will be 82.0° F and the “Deadband” will be 3.0° F.
Item #4 Shows the Enabling Relay to be the “TW Spray Pump” output
configured on (Relay #3). This means that in addition to the “Tower
Return” temperature being above setpoint the “TW Spray Pump” output
must also be activated for the “TW Fan VFD” to modulate.
Item #5 indicates it also has Output Limits of :
Max Voltage = 10.0 VDC
Min Voltage = 0.0 VDC.
Item #6 shows that its calculation settings are:
Calculation Interval (Controls Speed) = 3.0 Sec
Proportional Control Window = 1.0° F
With this configuration sequence the “TW Fan VFD” will modulate its
speed towards 100% (10.0 VDC) when the “TW Return” temperature”
(AIN2) is 3.0° F above the 82.0° F setpoint (85.0° F) and the “TW Spray
Pump” (Relay #3) output is active.
When the “TW Return” temperature” (AIN2) is between 85.0° F and
79.0° F and the “TW Spray Pump” (Relay #3) output is active, the TW
Fan VFD” will maintain its speed at a constant level.
The “Tower Fan VFD” will modulate its speed towards 0% (0.0 VDC)
when the “TW Return” temperature” (AIN2) is 3.0° F below the 82.0° F
setpoint (79.0° F) and the “TW Spray Pump” (Relay #3) output is active.
If the “Tower Spray Pump” (Relay #3) is deactivated the “Tower Fan
VFD” (AO #1) will move to 0% (0 VDC).
Relay Output #8
In this example Relay Output #8 is configured for the “System Active”
relay. In
Figure 32
Item #1 it indicates it has a Main Control Method
of “Follow Inactive Binary Input”.
Note:
The Emergency Shutdown switch or contact closure is
usually a normally closed contact. This means it will open
to activate to cause a Emergency Shutdown condition.
That is why it is selected to “Follow Inactive Binary
Input” instead of “Follow Active Binary Input”.
Item #2 indicates the “Binary Input to Follow” for this relay will be the
“Emerg Shut Down” binary input (BIN8).
No other settings are required for this relay output.
With this configuration sequence the “System Active” (Relay #8) will
deactivate turning off the “System Active” relay (Relay #8) when the
“Emerg Shut Down” binary input (BIN8) is activated (opened).
33
WSHP Loop Controller
GPC-XP Guide
