User Manual

CM2N8895en / 26.02.01 Siemens Building Technologies
2/4 Landis & Staefa Division
The following illustration shows the plant control elements in the electrical and
mechanical plant and in the VISONIK BPS.
PLTn
TSP
$030
$040
$050
$060
8895Z01en
Electrical and mechanical part
VISONIK BPS
DDC
program
Heating
valves
Fan
Plant
commands
Plant
elements
Manual
Damper Pump
Operating state table
Remote
Fault
The plant control elements shown are:
Elements Description
Plant elements All plant elements such as dampers, pumps, heating valves, etc. are
shown in the VISONIK BPS process image as physical data points
and are controlled via the DDC program.
For simplicity’s sake, only those plant elements addressed by plant
control are shown as data points together with their addresses
(damper $030, pump $040, etc.).
Plant
commands
Plant commands come from various sources and have an effect on
the operating state of the plant, for example:
− Remote: VISONIK DCS data and communication server.
− TSP: VISONIK BPS time switch program.
− Manual: Operator input to the VISONIK BPS.
− Fault: Error in plant / plant faults.
PLTn All interventions influencing plant operation are run by a single data
point, the PLTn plant point. The DDC program uses the plant point to
calculate the valid desired plant state cyclically and forwards this
calculation to the operating state table.
The PLTn plant point is a virtual point, i.e. its address is “n” and it has
assigned parameters; however, it has no hardware of its own in the
electrical and mechanical plants. Each plant has its own PLTn.
Operating state
table
The operating state table gives the various desired plant states (ON,
OFF, etc.) for each plant element. The plant elements are operated
according to the valid set plant state.
DDC program The DDC program controls and coordinates all activities for the plants
controlled by the VISONIK BPS according to the individual plant tasks
(in the DDC program) and the current state of sensors, setpoint units,
and plant commands.
Plant control
elements
Example
Explanations
(illustration)