in input, greater than noise level, but not so great as to damage
equipment.
3. Setting time: time it takes PID output process variable to
settle down after a process disturbance. For automatic tuning,
time interval between setting PID output to control point and
beginning of tuning cycle. For adaptive tuning, minimum time that
will be observed between parameter calculations.
4.
Maximum overshoot:
percent allowed.
5. Target damping: desired reduction in process variable
overshoot from first overshoot (maximum overshoot) to second, in
percent.
6. Noise band: minimum process variable perturbation that will
initiate adaptive calculation of PID parameters, in percent of
input range.
m.
Controller shall be provided with protocol converter/gateways with
EIA ANSI/TIA/EIA-485-A multi-drop communications port for
controller LAN network interconnection to field panel controller
[and to supervisory computer workstation].
2.5.7
Plant Master Controller
a.
Plant master controller [shall match individual boiler master
controller[s] and] shall provide for proportional, integral, and
derivative (PID) control of firing rate demand based on steam
header pressure. [The plant master controller shall be located in
the boiler No.1 cabinet.] The output of the plant master
controller shall go to the boiler master plant master controller.
The controller shall provide for digital display of the following:
1.
Controller output.
2.
Steam pressure.
3.
Steam pressure setpoint.
4.
Outdoor temperature.
5.
Total plant steam flow.
b.
Inputs shall be as follows:
1.
Steam pressure (Analog).
2.
Steam flow signal from individual boiler (Analog.)
3.
Outdoor temperature (Analog).
[4.
Fuel oil temperature (Analog).]
[5.
Fuel oil pressure (Analog).]
[6.
Natural Gas pressure (Analog).]
c.
Outputs shall be as follows:
SECTION 15561A
Page 45
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