AVL AVL DiCom 4000, Service Manual

Page: 39 / 182

4000 Evaluation Unit
Service Manual 4-7
−
SLAVE (Isotec mode)
The computer periodically sends a query to the instrument. If the instrument is
not ready for data transfer, NAK is transmitted to the computer. If measurement
data is available, a data block is transmitted to the computer.
−
NO (interface not activated)
Serial interface cable:
Pin assignment pin assignment
AVL 4000 PC
(9-pin SubD) (9-pin SubD)
2
3
5
4
6
8
2
3
5
TxD
RxD
GND
Fig. 4-3
4.2.1.5 Display Control and Softkey Connection
The display is operated by means of the SED 1335 LCD Controller with 32 to 128 KB of
display RAM.
In addition, the contrast voltage and the supply voltage for the CCFL background
illumination is generated by an inverter module on the main board. The contrast voltage
can be fine-tuned via an EPA channel of the 196 NT and temperature-compensated by
display-dependent characteristic curves.
The connection cables of the various displays are coded for ease of identification.
The 8 keys (softkeys and permanent keys) are addressed by ESD-protected drivers.
4.2.1.6 Generation of Auxiliary Voltage
Various voltages are generated from the 4 power supply unit voltages (5 V,
±
15 V, 24 V):
±
15 V analogue filtered voltages for powering the analogue circuits
Vpp (+12 V) switchable programming voltage for flash eproms
+ 5.12 V analogue precision reference voltage for ADC channels in the 196NT
- 5 V analogue negative supply for low-cast multiplexer and op amps
4.2.1.7 Board Control
The printer board (optional) and chamber adapter board (for AVL DiCom 4000) are
plugged straight into the main board, whereas the pneumatics board, speed/angle board
and free slot are connected via control or ribbon cables.
The speed/angle board and free slot are served by fast, synchronous, serial interfaces
(SSIO) of the 196NT which means that both intelligent pcbs with their own processors
and non-intelligent boards can be connected via parallel-serial converter I/O modules. In
addition, digital synchronisation signals, interruption inputs, analogue channels and
timer channels (EPA ports) are available for both boards.
The various equipment configurations are registered automatically which reduces the
time and cost of programming and set-up.
Bridge 4-6-8