Operating Instructions

Chapter 1—Introduction
Principles of Field Panel Operation
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Siemens Industry, Inc.
Owner's Manual
588-682
Building Technologies
2019-01-25
Principles of Field Panel Operation
The TC Compact Series gathers information about the environment of your facility, as
well as the equipment it monitors and controls. The TC Compact receives updated
information, stores information, executes control programs, handles operator
commands and requests, and makes control management decisions. At the same
time, the TC Compact also translates decisions into actions and allows the operator to
observe those actions. The operator can also override and modify the decisions made
by the TC Compact.
Gathering and Processing Field Inputs
The TC Compact samples the information at all field inputs, or points, approximately
once each second, and stores numerical representations of the sampled values.
Under certain conditions, some points require additional handling. The TC Compact
initiates required actions after these points are checked against previously-entered
configuration data.
Example
A log entry might be required in a point history file every 20 samples, or notification of
an alarm condition could be sent to the operator as a point crossed the alarm
threshold.
Executing Control Programs
The TC Compact continuously executes a user-defined set of instructions called the
control program. This program uses the most recent point values and the most recent
clock time. The control program does the following:
● Evaluates control strategies.
● Uses an internal calendar and time clock for time-based functions.
● Updates point values and commands field points according to the program results.
● Sends messages or reports to proper terminal locations as needed.
Example
During occupied hours (7:00 A.M. through 5:00 P.M.) a fan:
● Turns ON if the room temperature rises above 80°F (27°C).
● Turns OFF when the temperature drops below 73°F (23°C).
Between 5:00 P.M. and 7:00 A.M. the fan turns OFF regardless of the room
temperature.
If the temperature rises to 85°F (29°C) at any time, the TC Compact sends an alarm
message to an alarm printer.
These specifications can be met by:
1. Connecting a room temperature sensor/transmitter and fan starter output to the TC
Compact.
2. Defining the room temperature sensor with a high alarm limit of 85°F (29°C) and
the fan points in the TC Compact database.
3. Writing a short control program that defines your control strategy.
4. Enabling the execution for that portion of the control program.
To perform this control strategy, the TC Compact: