The I/O PCB is equipped with a built in Low Volt Power Supply (LVPS). This power supply generates 3 DC voltages: +24V, +15V and +12V [1].
These voltages are used to power low volt circuits on the I/O PCB and also to power external devices like Probes, Axis Brakes, and User Inputs.
There are 3 LEDs that show the presence of these voltages on the I/O PCB.
- When the I/O LVPS is working correctly these LED's will glow solid.
- When there is a short circuit on the low volt circuits these LED's can begin to flash on and off.
- When this happens you will need to find the source of the short circuit, start by disconnecting devices that are being powered by the LVPS like the Probe, Axis Brakes, User Inputs until LED lights begin to remain solid.
- When the LED's are OFF and the machine is turned on. The I/O PCB may not be getting the 115VAC Voltage input [2] or the Circuit Breaker for the I/O PCB may have tripped.