Super Systems 3 Series - Manual (Page 52)

Operations Manual Series 3
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Channel 2 Deadband. In controllers fitted with a second (cool) channel a parameter ‘D.BAND’ is also available in the Control list,
which sets the distance between the heat and cool proportional bands. The default value is 0% which means that heating will
turn off at the same time as cooling turns on. The deadband may be set to ensure that there is no possibility of the heat and cool
channels being on together, particularly when cycling output stages are installed.
Minimum Pulse Time. If either or both of the output channels is fitted with a relay, triac or logic output, the parameter ‘-.PLS’
will appear in the relevant output list (IO-1 list, OP-2 list, OP-3 list or AA Relay Output list). This is the cycling time for a time
proportioning output and should be set correctly before tuning is started.
Input Filter Time Constant. The parameter ‘FILTER TIME’ should be set before tuning the loop. It is found in the INPUT List.
Valve Travel Time. If the output is a motor valve positioner the parameter ‘MTR.T’ (Control List) should be set to the time that it
takes for the motor to travel from its fully closed to its fully open position.
Other Considerations
• If a process includes adjacent interactive zones, each zone should be tuned independently.
• It is always better to start a tune when the PV and setpoint are far apart. This allows start up conditions to be measured and
cutback values to be calculated more accurately.