Advertisement
EPS Inverter
ACW limit level
Auto in progress
MM alarm switch
SM alarm switch
Truck moving
High resol AD
Wheel angle
Slope peak
When the maximum angle limitation via feedback sensors is enabled (option LIMIT
DEVICE to ON) and the FEEDBACK ENC is lower than the inferior limit for the
steered wheel angle limitation, the steered wheel angle will be limited and ACW
LIMIT LEVEL turns ON (active).
Provides real time the information the eps-ac0 follows the manual command (AUTO
INPROGRESS is OFF) or is executing an automatic centering (AUTO IN
PROGRESS is ON).
It is On when the safety contact belonging to the main uC is closed.
It is On when the safety contact belonging to the slave uC (supervisor) is closed.
It provides the state of the travel demand for driving the truck.
This information is obtained either with the travel demands directly connected to
CNA#1 or via CAN Bus (depending by the state of the CAN BUS setting).
It turns ON when the set point potentiometer is processed with a high resolution AD
(it occurs when the set pot potentiometer is close to the straight ahead position and
SET HI RESOL AD is Level 1).
It provides the current angle of the drive wheel by the degree.
This reading is just for debugging the maximum slope of the potentiometers
connected to the epsac0.
Especially for not redundant sensor equipments (just a single command
potentiometer or just a single feedback potentiometer without encoder) a concern
regarding the safety raises: if a single potentiometer fails a sudden movement of the
steered wheel may occur with danger. To avoid this problem it is necessary to detect
any failure in a single potentiometer. This is hard to do because the failure mode can
be quite different. Anyway, the best countermeasure we can take is to seek for the
wiper voltage changes faster than its physical limit. In fact, for the limited speed of
the steering motor(or of the steering wheel), the slope in the wiper voltage must be
limited under a certain threshold. When this slope threshold is overtook, the
potentiometer may be assumed broken. So, it is useful to measure the maximum
slope occurring in your application when right working, in order a right slope
threshold can be chosen to avoid an alarm occurs when the potentiometer is not
failed.
The SLOPE PEAK reading in the tester menu is a real time measurement of the
slope peak of the potentiometers. In particular:When the special adjustments
DEBUG OUTPUT is other than Level 12 or 13, SLOPE PEAK supplies the slope
peak of the CPOC1 set point potentiometer (CNA#9).When the special adjustments
DEBUG OUTPUT is Level 13, SLOPE PEAK supplies the slope peak of the CPOT
feedback potentiometer (CNB#6).
When the special adjustments DEBUG OUTPUT is Level 12, SLOPE PEAK
supplies the slope peak of the CPOC2 set point potentiometer (CNA#8).The SLOPE
PEAK measurement is the difference between two AD conversions of the selected
potentiometer picked up with 16 msec long interval. The SLOPE PEAK reading can
be converted in a Voltage change (V in volts) of the wiper voltage in an interval 16
msec long, with the formula :
V = SLOPE PEAK*5/1024 = Voltage change in Volts in 16 msec
(e.g. When SLOPE PEAK is 61 it means the selected potentiometer, in the worst
case, changes61*5/1024 =0.3 V in 16 msec.).
Obviously the SLOPE PEAK reading must be compared with the threshold for the
STEERSENSOR KO alarmThe STEER SENSOR KO alarm may be adjusted.
Description
7-48
Advertisement
