National Instruments Direct Injector Driver System Manual
© 2013 National Instruments. All rights reserved.
3.3.3.3 Proportional Solenoid
Valves to PFI Lowside Channels
The lowside drivers of the PFI Driver module are capable of driving a wide variety of automotive relays and
proportional solenoid valves. Examples of actuators include EGR valves, turbocharger wastegate valves, fuel
pressure regulators, or any single-solenoid-actuator which draws less than 1.5 amps. The DI Driver System provides
a software mechanism to combine adjacent channels to double the current capacity. Refer to the
for information about locking LS channels together for synchronized operation.
Each LS channel is independently controlled via pulse-width modulation (PWM). PWM duty cycle from 0 to 100%
is possible. Each PWM controller utilizes a 20-bit timer operating at 2 MHz. This provides a resolution of 500 nsec
and a minimum PWM frequency of 2 Hz. Since 0% and 100% duty cycles are possible, relays and actuators may be
controlled in continuous on or off states.
Wiring diagram for up to four relays or proportional solenoid valves to the LS channels of the PFI Driver module: (NI
recommends using 18 AWG wire (or larger) for connected devices.)
Figure 3.3.3.3.a, Connecting general purpose solenoids to the low-side driver channels