4.
Pulse for fuel oil flow totalizer (Contact).
d.
Controllers shall be provided with protocol converter/gateways
with an EIA ANSI/TIA/EIA-485-A multi-drop communications port for
controller LAN network interconnection to field panel controllers
[and to supervisory computer workstation.]
2.5.9
Feedwater Controller
**************************************************************************
NOTE: Specify two-element boiler water level
control for smaller capacity plants with relatively
stable loads, such as space heating. Specify
three-element control for larger capacity plants and
unstable loads, such as industrial process and Navy
pier facilities.
**************************************************************************
a.
Feedwater controller shall match other controllers in system and
shall provide [two] [three] element PID control of boiler water
level in response to changing boiler level and feed forward signal
of steam flow. Controller shall automatically switch to single
element feedwater control strategy during cold startup when steam
and feedwater flow signals are not active. Controller digital
displays shall be as follows in their respective engineering units:
1.
Controller output.
2.
Water level.
4.
Steam flow.
5.
Feed water flow.
b.
Controller inputs shall be:
1.
Water level.
2.
Steam flow.
3.
Feed water flow.
4.
Remote alarm silence (Contact).
c.
Controller outputs shall be:
1.
Feedwater control valve (Analog).
2.
Remote audible alarm (Contact).
3.
Steam flow (Analog).
d.
Controllers 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 controllers
[and to supervisory computer workstation.]
SECTION 15561A
Page 47
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