dunphy TD - Modulation Modes and Lockouts

Operating Instructions For TD/TAD4 Dual Fuel Burner
June 13 55 of 165 TD/TAD4 Manual Rev 4
State
no.
State name
Description
16.
Modulation
When t8 has elapsed the fuel and air motors are modulated
according to the demand placed on the burner. If the fuel
selection is changed or the ‘burner on’ signal (PE9) is removed,
the main valve output(s) are turned off. A flame and air
pressure signal must be detected or the controller will lockout
the burner and move to stage 0.
17.
Move to post-
purge
If Post Purge is not selected then the controller returns to state 1
to wait for another start-up.
If Post Purge has been selected then the fuel servo motor is
moved to its closed position, and the selected air motor(s) are
moved to their post purge position(s).
18.
Post-purge
When the air drive(s) have reached their post purge positions
then the Post Purge Time (t9) is started. When t9 has elapsed,
the burner motor is turned off and the controller returns to state
1 to wait for another start-up.
5.3 Modulation
During stage 16 (modulation), the controller will position the fuel and air motors within the
programmed profile appropriate to the requirement for heat. The controller has 2 modes of
operation using the standard RATIOTRONIC modulation function, Normal and Local. The mode
of operation is set via the keypad by pushing the “Burner ON/OFF” key and selecting the mode.
Using the programmable block function (option) within the controller it is possible for the
modulation control to be generated with customised options, these are not covered in the standard
manual.
5.4 Normal mode
In Normal mode, the modulation rate is determined by the internal PID control settings, Manual
modulation from the keypad, or by one of the following remote influences:
 Auxiliary modulation input,
 Digital set point selection
 Serial communications – Comview or Lead/Lag.
5.5 Local mode
In Local mode, the modulation rate is determined by either the internal PID settings or Manual
modulation via the UP/DOWN keys. External modulation inputs and set point selection inputs are
ignored.
When “Local1” is displayed the burner is running using the Set point 1 PID settings.
When “Local2” is displayed the burner is running using the Set point 2 PID settings.
5.6 Non-volatile lockout
Non-Volatile lockouts cannot be cleared without operator intervention and are remembered in the
event of power being removed from the controller.
A non-volatile lockout will occur under the following conditions: