AFMNA0AA – EPS-BLI HYG – User Manual Page – 15/75
5.3.2 Straight ahead toggle switch
The straight ahead toggle switch must be of NPN type (i.e. it must connect B- to
CNA#3). A possible arrangement for the straight-ahead switch (proximity switch) is
shown in Figure 4-6 below. The proximity switch is connected to the truck frame; the
iron plate rotates together with the steered wheel.
Figure 5.3.2-1. Straight-ahead toggle switch.
5.4 Sensor in the steering command
Closed-loop steering mode relies on a steering command device in the tiller of the truck
in charge of transmit the steering set point to the E-steering controller. This solution
implies mechanical hard stops and a rigid one-to-one relationship between steering
command position and steered wheel position (tiller is always aligned with the steered
wheel in the straight ahead direction). A disadvantage of this arrangement is that the
steered wheel automatically moves at key-on to recover the relaxation occurred after
past session key-off.
5.4.1 PWMs type sensor
This option provides high noise rejection and little failure-mode list. This sensor
consists of two independent PWM type outputs with a 200 Hz ± 40 Hz frequency and a
duty cycle in the range 5% to 95% per revolution programmed with triangle wave
shape 90° shifted (see figure 5.4.1-1). Quasi-redundant or fully-redundant set point
sensors may be adopted.
Figure 5.4.1-1.
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