CleaverBrooks Hawk 1000, Руководство по эксплуатации

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Hawk 1000 Section 5 — Commissioning
Part No. 750-366 5-17
5.11 Two Boiler Lead Lag
The Hawk 1000 uses dual setpoints to accomplish “Lead Lag” control in a two boiler control scheme. The
setpoints are based on each boiler's local steam pressure (for steam boilers). The “Master” boiler has a selector
switch, which designates each of the two boilers as lead, or lag. There are two contacts for the two position
selector switch.
Dual set point option via digital input must be selected when unit is being configured.
The first contact is used to provide a digital input to Boiler #1 PLC (I: 5/14) to designate this boiler as the
lead boiler. The second contact of the selector switch is used to provide a digital input to Boiler #2 PLC (I:5/
14) to designate Boiler #2 as the lead boiler. With input energized set point 2 is selected. Set point 2 is
designated for the boiler operation when it is selected as lag unit.
This selection dictates which of the boilers will be using set-point #1 and which will use set-point #2. The
two boilers will then start and stop, based on those set-points. These set-point values are set in the panel view
screen. It is important to set the set point 1 higher then set point 2.
The Hawk 1000, however, will not perform unison modulation. The Hawk 1000 does not use a header steam
pressure (or hot water temperature) transmitter for lead lag controls, just the local steam pressure (or hot water
temperature) transmitter on the boiler.
Figure 5-29. Dual Setpoint, Dual SP Signal Select
Figure 5-30. 2 boiler lead lag wiring, typical