REV 0, June 2005 Page 25
Operation Manual SUPREMA
3. Description of the System
The data is exchanged between the modules over the CAN bus. All modules use standardised
device profiles according to CANopen (CiA-DS 301, CiA-DS 302, CiA-DSP 401 and
CiA-DSP 403). Two CAN bus connections are provided, which are operated in parallel in the
redundant system design.
3.5 Bus Protocol
On layers 1 and 2 of the ISO/OSI model according to ISO Standard 11,898, the CAN bus
protocol 2.0A is used with 11 bit long identifiers. On the Interconnection Board (MIB module),
the DIL switch can be used to set the transfer speed to 10, 20, 50, 125, 250, 500 or
1,000 kBits/s for all of the connected modules. All modules on one bus must operate at the
same bit rate; if one of the modules uses a different rate, an error state occurs on the bus. This
is detected, and appropriate messages are displayed.
Each module receives a code (Node ID) in the range of 1 ... 127 by the use of the DIL switch of
the MIB module board on the basis of its slot in the rack. Each of the modules on one bus must
have its own code. If duplicate codes are detected, an error message is generated.
3.6 Descriptions of the Modules
3.6.1 Measurement Value Input (MDA-/MAI-/MAR-/MPI-/MFI-/MSI-/MCI-Module)
The measurement values are acquired by means of the following units:
• MAI Module: ANALOGUE INPUT Module
(signal processing + digitisation for 8 inputs)
• MAR Module: ANALOGUE REDUNDANT UNIT
(redundant signal input, digitisation)
• MPI Module: PASSIVE INPUT UNIT
(signal processing for passive catalytic and semiconductor sensors)
• MCI Module: CURRENT INPUT UNIT MCI 10 (signal processing for 0 ... 20 mA,
0 ... 24 V, contact)
MCI 20 (signal processing for 0 ... 20 mA)
MCI 20 BFE (BFE = Smoldering Fire
Detection)
(Signal processing for 0 ... 20 mA
especially for DF 8501, DF 8502,
DF8510 fire detectors)
• MFI Module: Fire Input Module
(Power supply and signal processing for automatic and push-button fire detectors)
• MSI-Module: Switch Input Module
(Power supply and signal processing for external switches)
• MDA Module: DATA ACQUISITION UNIT
(measurement signal processing)
MAI Module: Analogue Input Unit
The MAI module is provided to operate 8 sensors and to process the input signals of those
sensors. The power supply outputs for the sensors and the signal inputs are protected against
short-circuits and overloads in the 24 VDC power system.
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