Function Principle; Standard Controller - Siemens SIPART DR22 Manual

1 Technical Description

1.4 Function principle

1.4.1 Standard controller

1.4 Function principle
1.4.1 Standard controller
The standard controller consists of three function blocks:
-- Power supply unit
-- Front module
-- Main board
Power supply unit
Primary clocked power supply plug with high efficiency for AC 115/230 V (switchable) or for UC
24 V. It generates the secondary internal supply voltages +24 V and +5 V from the power
supply. The metal body is mounted on PE conductors (protection class I). The power supply
and internal supply voltages are isolated from each other by safe separation by a protective
shield. The internal supply voltages are functional extra-low voltages due to overvoltage cutoff
in the event of an error. Since no other voltages are generated in the instrument, these
statements apply for all field signal cables (used standards, see chapter 1.6, page 127). A total of
450 mA are available for the outputs L+, AA and BA due to the design for a high power output.
Front module
The front module contains the control and display elements and the appropriate trigger compo-
nents for the displays.
All display elements are designed in LED technology which provides a longer service life and
higher light density as well as a good viewing angle. The control elements are short-stroke
switches with a tangible "pressure point" and high return force.
Main board
The main board contains the field signal conditioning of the standard controller, the CPU
(Central Processing Unit) and the connections (through the interface board) to the module slots.
The field signals are fed through protective circuits for external static or dynamic overvoltages
and then adapted to the signal levels of the CPU by the appropriate circuits. This adaptation is
performed for the analog inputs, the analog outputs and the digital outputs by modern thick-film
circuits.
The microcontroller used has integrated AD- and DA converters and operates with 32k battery-
backed RAM. The user-specific configuration is stored in an user program memory with a serial
4k EEPROM. When replacing the main board the user memory can be plugged from the old
onto the new module. The whole CPU is designed in C-MOS technology.
A process image is generated at the start of every routine. The analog and digital inputs and
actuation of the front buttons is included and the process variables received from the serial
interface are accepted. All calculations are made with these input signals according to the
configured functions. Then the data are output to the display elements, the analog outputs and
the digital outputs as well as storage of the calculated variables on standby for the serial
interface transmitter. The interface traffic runs in interrupt mode.
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Manual
SIPART DR22 6DR2210
C79000-G7476-C154-03