B&R PROVIT 4000, User Manual

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4.3.14 ENHANCED AT KEYBOARD CONNECTION
The connection of an external enhanced AT keyboard can be made via a 5 pin DIN connector on left side of
the PROVIT 4000 Industrial PC. The external AT keyboard works in parallel to the built-in matrix keyboard and
to optional keypad modules.
The connection can handle a max. 0.5 A.
The keyboard should only plugged in or unplugged with the power disconnected.
4.3.15 COUPLING TO THE KEYBOARD PROCESSOR
The coupling circuit board can be found above the fan. This circuit board establishes the connection from to
the keyboard processor in the display unit.
4.3.16 CONNECTION CONTROLLER - DISPLAY
The connection between the controller and display is made with a plug on the coupling circuit board.
4.3.17 WATCHDOG
The PROVIT 4000 Industrial PC is equipped with a Watchdog. The Watchdog is only activated after the
I/O address 312h is accessed.
At this point in time, the I/O address must be re-accessed inside a time window of between 25 µsec and
70 msec. If the next access does not take place inside of 70 msec, a reset will take place. If access is made
too fast (access time < 25 µsec), a reset will also take place.
If a Watchdog error occurs, the WD LED is lit. The WD LED remains lit until the device is turned off.
4.3.18 TEMPERATURE MONITORING
Temperature monitoring consists of the evaluation of the three temperature measurement points. The three
measurement points are:
- CPU (processor)
- Display
- Power Supply
If one of the three measurement points measures a temperature that is too high, a corresponding bit in the
I/O address 302h is set (see section "5.5 Temperature Monitoring"). Additionally, the TEMP LED on the display
unit is lit.
Pin Assignment
1 Keyboard Clock
2 Keyboard Data
3 n.c.
4 GND
5 +5 V