User Manual

CM2N8883E / 10.1999 Siemens Building Technologies
2/4 Landis & Staefa Division
The physical basic functions in VISONIK systems are closely related to I/O module
points and I/O modules. They physically connect the BPS via the P-bus (process bus)
and field wiring to the inputs and outputs of the devices in technical installations as
shown below (simplified illustration):
MLST
SB
MW
BPS
P-bus
8883Z02E
I/O modules
Point types
The I/O modules transform the various signals of the plant components to uniform
signals of the VISONIK BPS and vice versa. The I/O module range comprises modules
to cover all basic building automation functions. Each basic function is assigned the
associated point type in the VISONIK BPS:
Basic function Point type Example
SIGNALLING ML
Signalling contact, continuous signal (normally open
contact/normally closed contact)
MEASURING MW Sensor, e.g., with Ni1000 element
COUNTING ZW Counting pulse transmitter for electric and gas demand
SWITCHING SB Relay output, continuous command, mono-stable
POSITIONING ST Positioning signal 3-point or continuous for mixing valve
In the VISONIK BPS, up to 224 I/O module points with the respective basic functions
can be generated. Addressing at the I/O modules occurs via address plugs.
In accordance with VDI 3814, virtual basic functions represent information derived or
generated from physical or processing functions. These functions are available in the
form of information points for further processing similar to the physical basic functions.
Example for measuring:
The virtual basic function MEASURING is the result of the physical basic function
MEASURING and the processing function "Convert raw measured value to physical
unit“; e.g., analog input AI of VISONIK BPS: AI is the current, converted measured
value (°C) in point type MW.
The values of all physical and virtual basic functions in the VISONIK BPS can be
communicated to the management level where they are processed and displayed.
Access to the basic functions from the management level is possible, but it is subject to
the required functionality and the assigned access rights.
Basic functions
Physical basic
functions
Explanations
(illustration)
Number of I/O module
points
Virtual basic functions
Communication with
management level