CEMP-E
TI 811-12
18 August 1998
independent (stand-alone) mode performing the monitoring and control routines using applications
software programs and operating parameters stored in the smart field panel's memory.
b. The smart field panel collects data from instruments interfaced to the utility systems and
generates commands to control operating devices such as valves, dampers, motors, and relays. The
smart field panel's capabilities include control of all physical parameters such as space temperature,
space humidity, and supply water temperature without requiring data or operating parameters from the
central/island station. The smart field panel also responds to central/island station requests for
equipment operating data and status. The smart field panel transmits alarms to the central/island station
for conditions such as high and low temperatures, pressures, flows, unauthorized equipment operation,
and field hardware malfunction. Commands from the operator's workstation can result in the downloading
of new or revised parameters to adjust setpoints or change operating parameters of equipment.
c. The smart field panel must include sufficient memory to contain the operating system,
applications software, database and control sequences for all required operation. Volatile memory is
required to be backed up in event of power loss. Software stored in non-volatile memory does not have
to be downloaded from the central/island station after an interruption of power occurs.
d. The smart field panel must be equipped with a battery backed internal real time clock function to
provide a time base for implementing time dependent programs. The smart field panel's real time clock
must be updated by the central/island station at least once a day and upon resumption of
communications with the central/island station after any data transmission system interruption.
e. A communication interface in the smart field panel converts the data output of the smart field
panel to a signal compatible with the site specific data transmission system for communications with the
central/island station. The communication interface must transmit and receive data at rates sufficient to
support system response requirements.
f. Resumption of power after an outage will cause the smart field panel to automatically restart and
establish communications with the central/island station. If the smart field panel is unable to establish
communications, it must still perform all required functions while saving certain data for later uplink to the
central/island station. Smart field panel shutdown based on a self-diagnosed failure in the power supply,
hardware, or software must set each piece of controlled equipment to a predetermined failure mode.
g. In the situation where the smart field panel will be required to continuously collect data to be
transmitted to the central/island station, it will be necessary to provide an uninterruptible power system (in
lieu of the power line conditioner) for the entire smart field panel as well as any sensor and controller
power required.
h. The smart field panel functionally includes the remote terminal units associated with it whether in
the same enclosure or remotely located. The relationship between the central/island station, smart field
panels and remote terminal units is shown in Figures 4-2 and 4-3.
4-2
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