CEMP-E
TI 811-12
18 August 1998
CHAPTER 7
APPLICATIONS SOFTWARE
1.
GENERAL DESCRIPTION.
a. Applications software includes programs which monitor and control the operations of various
HVAC, mechanical, and electrical utility systems, as well as other site specific programs providing
building support functions. Examples of specific applications programs include energy conservation
programs, equipment selection programs, and utility demand limiting programs. The designer will select
the appropriate instrument inputs and control outputs to be used with selected applications software as
defined in the database table.
b. Depending on the requirements of the application, applications programs may use adaptive
control techniques that allow the UMCS to monitor its own past performance and automatically adjust its
parameters for optimum performance.
c. The applications software programs discussed in this section are not listed in the order of the
highest potential energy or cost savings. The determination of cost effective programs for each building
or system is made after the savings and economic calculations are completed. The amount of cost
savings depends on factors such as existing building type, equipment condition, equipment performance
and operating schedules.
d. Most applications software programs apply to both direct digital control (DDC) and supervisory
control implementation. Depending on the system sequence of operation, the specific programs selected,
the site-specific implementation, and the configuration of the controlled equipment, UMCS outputs based
on the operation of applications programs may be binary (or change of state) control signals, analog
signals to directly modulate final control elements such as valves or dampers, control point adjustment
(CPA) signals or software adjustment to a sequence of operations.
e. For supervisory control implementation, CPA will be implemented by using an AO or a pair of
DOs in conjunction with an AI signal from sensors to achieve changes in operating setpoints through the
CPA port on a local loop controller.
2. SCHEDULED START/STOP PROGRAM. The scheduled start/stop program consists of starting and
stopping equipment based on the time of day and day of week. Scheduled start/stop is the simplest of all
UMCS functions to implement. This program provides the best potential for energy conservation by
turning off equipment or systems during unoccupied hours. In addition to sending a start/stop command,
it is mandatory to have a feedback signal indicating the status (on-off or open-closed) of the controlled
equipment. The feedback signal verifies that the command has been carried out and provides the UMCS
operator with an alarm when the equipment fails or is locally started or stopped. Design requirements for
this applications program will be indicated by the letter X adjacent to the program listing on the
appropriate database table, as shown in Chapters 8 and 9.
a. Field hardware requirements. The hardware requirements are:
(1) UMCS input from utility system. Equipment status from pressure switch, auxiliary contacts,
flow switch or current sensing relay/transducer.
(2) UMCS output to utility system. Start/stop control signal from UMCS to interposing relays
(momentary or maintained signal as required by the equipment control circuit configuration and failure
mode) - one for each piece of equipment.
b. Software I/O requirements. The software requirements are:
7-1
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