on high-level controllers, provide at least one similar spare output point
per controller.
a.
Analog Outputs: Provide controllers with 10 bit minimum output
resolution. Output shall be 4 to 20 mA, 0 to 10 VDC, or 0 to 20
psig. Each pneumatic output shall have feedback for monitoring of
the actual pneumatic signal.
b.
Digital Outputs:
Provide contacts rated at a minimum of 1 ampere
at 24 volts.
2.1.1.9
PID Control
Provide controllers with proportional integral, and derivative control
capability. Terminal controllers (TCV) are not required to have the
derivative component.
2.1.1.10
Digital Controller Networking Capabilities
The upper level digital controllers shall be capable of networking with
other similar upper level controllers. Upper level controllers shall also
be capable of communicating over a network between buildings.
2.1.1.11
Communications Ports
a.
Controller-to-Controller LAN Communications Ports: Controllers in
the building DDC system shall be connected in a communications
network. Controllers shall have controller to controller
communication ports to both peer controllers (upper level
controllers) and terminal controllers (lower level controllers).
Network may consist of more than one level of local area network
and one level may have multiple drops. Communications network
shall permit sharing information between controllers, allowing
execution of dynamic control strategies, and coordinated response
to alarm conditions. Minimum baud rate for the lowest level LAN
is 9600 Baud. Minimum baud rate for the highest level LAN shall
be 9600 Baud. Minimum baud rate for a DDC system consisting of a
single LAN is 9600 Baud.
b.
On-Site Interface Ports: Provide a RS-232, RS-485, or RJ-11
communications port for each digital controller that allows direct
connection of a computer or hand held terminal and through which
the controller may be fully accessed. Controller access shall not
be limited to access through another controller. On-site
interface communication ports shall be in addition to the
communications port(s) supporting controller to controller
communications. Communication rate is 9600 Baud minimum. Every
controller on the highest level LAN shall have a communications
port supporting direct connection of a computer; a hand held
terminal port is not sufficient. By connecting a computer to this
port, every controller in the direct digital control system shall
be accessible and programmable.. The following operations shall
be available: downloading and uploading control programs,
modifying programs and program data base, and retrieving or
accepting trend reports, status reports, messages, and alarms.
c.
Remote Work Station Interface Port: Provide one additional direct
connect computer port in each DDC system for permanent connection
of a remote operator's work station, unless the workstation is a
SECTION 15910N
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