Diagnostic Features

The NI-9470 supports the following diagnostics features.

• Overcurrent detection—The NI-9470 has built-in circuitry to detect over-current fault on its DO+ outputs. If the fault occurs when the NI-9470 is outputting PWM on a channel, then the PWM engine will disable and drive the DO+ output low to COM.
• Field-side power supply fault detection—The NI-9470 has built-in circuitry to detect if voltages on its V_sup inputs are connected and operating within specification. If the fault occurs when the NI-9470 is outputting PWM on a channel, then the PWM engine will shut down and drive the DO+ output low to COM.
• Overtemperature detection—The NI-9470 has an overtemperature sensor to safeguard against excessive power dissipation within the module. If an overtemperature fault occurs when the NI-9470 is outputting PWM, all PWM engines will disable and drive all DO+ outputs low to COM.
• Field-side power supply voltage readback—The NI-9470 uses a delta-sigma ADC to measure the voltage on V_sup channels at a constant sample rate independent of the channel PWM frequencies. Refer to the Voltage Readback section of the NI-9740 Specifications for more information. You should configure voltage readback in its own loop separate from software loops on the per-channel output setpoint, current, and duty cycle readback.