AVL AVL DiCom 4000, Руководство по обслуживанию

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Evaluation Unit AVL 4000
4-52 Service Manual
4.24 4-/5-Gas Section
4.24.1 Pneumatics Board
The pneumatics board located on the pneumatics frame is responsible for supplying
mains voltage to the double exhaust gas pump and for monitoring the pneumatic
functions. The cable connections have plugs that cannot be mistaken.
The pneumatics system which supplies the 4-/5-gas measuring instruments unit with
fresh air, exhaust gas or calibrating gas is controlled by the main board.
The valve and the pump are addressed by the relevant commands. The fan is switched
from the main board and the pressure sensor that monitors the pneumatics systems is
handled by the main pcb.
4.24.2 Multi-gas Measuring System - General Requirements
The main components of the multi-gas measuring system are the measuring instruments
unit, the pneumatics and a ventilation system to cool the measuring instruments, power
supply unit and pump.
The multi-gas measuring system records the exhaust gas components CO
2
, CO, HC as
n-hexane and O
2
in petrol engine-driven motor vehicles (NO option available).
Connection of an electro-chemical oxygen sensor to the measuring instruments unit and
evaluation of the signal at the multi-gas measuring system.
Power supply to multi-gas measuring system: overall approx. 30 W output
Power is supplied via the Andros power supply unit
±
15 V
±
12 V
±
5 V
Power supply to the pneumatic components:
Pump 220/230 Volt, 50/60 Hz controlled by AVL board
NO sensor supplied via measuring system, shielded infeed lines
Solenoid valve driven by AVL main board (24 or 12 V)
Fan driven by AVL main board (24 V)
Pressure sensor 5 V from AVL power supply unit, integrated on pneumatics
board, evaluation by AVL processor
O
2
sensor Connected to measuring system, shielded line
Backflush option, 2 solenoid valves, controlled via AVL main board
(12 or 24 V)
The measuring system, leak test, low flow check, oxygen sensor test, control by protective
multiple earthing, the calibration, data evaluation and display of measurement data are
all controlled by the software on the AVL board. Also to be borne in mine are the
automatic measuring system control routines for the pump and solenoid valve (e.g.
protective multiple earthing, calibration).
The measuring system is a closed system. The control circuit, data transfer and status
message functions are linked to the AVL board via an RS 232 interface.