Interfaces 6
miriac EK-5744 User Manual
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© MicroSys Electronics GmbH 2017
6.8 Relay Output
The relay output on the EK-5744 can be accessed via the connector RLY. It is
rated for a maximum switch current of 2A at 30VDC. The save or unpowered state
is open. The switch contacts are isolated with no polarity limitation. It works as well
with AC as with DC voltages.
The relay can only be activated by the SBC and the CPU. Therefore the two lines
MCU-FSO and SBC-FSO# must be set active. The SBC-FSO# is derived from the
MC33907 pin FSOB. The MCU-FSO pin is connected to the MC5744P port D8 on
pad L4.
Basic schematics of the relay in the OFF state.
SBC-FSO#
MCU-FSO
Relais
0
0
off
0
1
off
1
0
off
1
1
on
Table 6-21: Relay Activation Truth Table
1
2
1
8
2
3
4
7
6
5
MCU-FS0
SBC-FS0
Figure 6-9: Relay and Digital Output Power Connector
Figure 6-10: Relay operating principle
