Power

UPAN Core runs from one DC power supply of 12–24 V. The power supply is not included: you choose and buy it. This page explains which supplies fit, how big they should be, why the input stops at 36 V, and how to wire the mains side. The drivers in the sockets, the logic and the sensor supply terminals all take their power from the same input.

Supply range

Connect the supply to the 2-pin PWR 12–24V terminal: pin 1 +, pin 2 GND (see Wiring). Use wire of at least 0.75 mm².

12 V is enough for a camera slider on a battery. 24 V is the usual choice: the TMC2209 drivers in the sockets are rated up to 29 V, and a higher voltage lets the motor keep its torque at speed. Between about 28 and 36 V the device cuts power to the sockets and reports why; use that range only with external drivers on the RS-422 terminals.

The supply voltage also appears on the +V sensor terminal (through a 200 mA resettable fuse). Sensors on that pin must be rated for it.

Choosing a power supply

Use a DIN-rail or enclosed supply from a known brand. These Mean Well models fit:

Prefer HDR, NDR or SDR. On overload these supplies limit current and sag a little at the acceleration peak. LRS supplies go into "hiccup" mode instead: they switch off for a moment, and the motor can lose steps.

Do not use a 48 V supply, not even turned down: 48 V models cannot be adjusted anywhere near 36 V. Do not use unbranded "24 V 10 A" supplies either: they usually lack real protection, overstate their power and carry fake CE marks.

Sizing per axis

A chopper driver draws much less current from the supply than the motor phase current: roughly ½ to ⅔ of the phase current, plus 30–50 % reserve.

For several axes on one supply, add up the figures per axis, and add about 5 W for the controller, the sensors and the outputs you switch.

Braking energy

A motor that decelerates works as a generator and pushes energy back into the supply line. A switching power supply cannot take it back, so the voltage on the board rises ("pumping"). There is no braking resistor on the board. What limits the pumping:

• Firmware. The controller measures the supply voltage and decelerates more gently when it rises.
• The over-voltage cut-off. If the voltage goes above about 28 V anyway, the sockets are cut off before the TMC2209 is damaged.
• Your choice of voltage. With heavy inertia (rotary tables, flywheels) or vertical loads, stay at 24 V or below.

Note: Pumping is still to be measured on prototypes. This is not final yet.

Mains wiring and grounding

• Connect protective earth (PE) to the earth terminal of the power supply. Connect the machine frame and the motor housings to PE.
• Feed the supply through a 2–6 A circuit breaker, type C.
• LRS supplies have a 115/230 V selector switch. Check it before the first power-on.
• Switch the power on and off on the mains side of the supply. Do not plug the DC terminal in live: it sparks at the terminal.
• Never connect or disconnect a motor, or plug a driver into a socket, while the supply is on.
• With an UPAN Axis module, run motor power from the supply to the module on its own wires (star wiring). The ribbon cable between the modules carries only logic signals and logic ground.

Power from USB

The USB-C socket can power the logic on its own, so you can set up the device or copy a package to it on a desk without the power supply. Drivers in the sockets cannot move a motor from USB (ERROR_NO_MOTOR_POWER). The USB budget is too small to power sensors or an external driver from the +5V pins. Connect the power supply before you move anything.

Heat

The TMC2209 drivers get warm; each comes with a heatsink, and the case has vents over the sockets. Mount the device on the DIN rail with free air above the vents, not closed in with a hot power supply. The drivers report over-temperature themselves, and the device stops the axis with a fault. Final case and mounting details are not final yet.