3.1 ENGINE CONTROL UNIT (DEUTZ EMR2) 3. INTRODUCTION TO THE ELECTRONIC SYSTEM OF THE TRACTOR 3. INTRODUCTION TO THE ELECTRONIC SYSTEM OF THE TRACTOR The electronic system of the Agrotron series includes control units by which the machine functions are managed. Each control unit is dedicated to the management of one or more systems.
The tractor's electronic system incorporates a socket used for calibration, diagnosis and programming of the control units; connecting the All Round Tester ® (ART) or a portable computer with SERDIA and EDS diagnostics software to the socket, the technician can program the operating parameters of the tractor according to the options available (front PTO, etc.), test the operation of the sensors and pushbutton controls, calibrate the sensors and carry out troubleshooting procedures. The ART can also be used to access a list of the alarms detected, which are stored as brief descriptive messages.
Through these messages, the technician can locate faults and, using the dedicated Test and Monitor menus, check the op- eration of system components. Using the portable computer and the SERDIA and EDS software, the technician can analyse information and alarms (if any) recorded by the engine, transmission and INFOCENTER control units and verify the correct operation of components and sensors governed by these units.
3.1 ENGINE CONTROL UNIT (DEUTZ EMR2) The function of the engine control unit is to supervise the correct operation of the engine; it receives commands from the operator by way of the hand throttle, the accelerator pedal or the MAX, MIN and MEM functions on the rpm control keypad, or on the armrest if fitted, and, according to the signal returned by the engine speed pickup, the coolant temperature and fuel temperature sensors and the turbo pressure sensor, will adjust the crankshaft speed by outputting a modulated volt- age signal (PWM) to the actuator of the injection pumps.
The engine control unit also pilots the operation of the glowplugs, activating the relative relay in response to signals re- ceived from the coolant and fuel temperature sensors to ensure easy starting even in extreme weather conditions. The engine control unit informs the operator of any malfunction affecting monitored components, by way of a warning light on the Infocenter. Faults are indicated by two types of signal: continuously flashing light: the control unit has detected a fault in one of the engine speed control components (ac- celerator pedal, hand throttle or keypad), though not a fault that affects the operation of the engine; light permanently on:
the control unit has detected a serious fault and responded by switching the engine off, disabling the starter circuit. Connecting the portable computer with the SERDIA software installed, the technician can display the alarms affecting the engine. The alarms management function of the engine control unit is based on two classes of alarms, defined active and passive. All alarms are displayed in a single window that shows information on the type of alarm detected, and the possible cause, indicating the number of recurrences and the status (active or passive). Detected alarms are recorded in two separate memory locations:
- Error memory 1, erasable by the technician - Error memory 2, which maintains a log of all alarms generated, indicating how many times an alarm has cut in and when was the most recent 20-13