Motor Interface Boards (MIBs)

Getting started

Application Notes

MIB Design

A Motor Interface Board carries the Puck's two board-to-board connectors, the motor phases, bus power and CAN, in whatever outline your application needs. The Puck does the control; the MIB does the mating, the routing and any peripherals.

Start from a reference design. The 16 mm MIB from the P4-16 Dev Kit is the smaller, simpler case — one Puck size, limited peripherals. The P4 Dev Board covers both P4-16 and P4-37 and includes power supply design and the full I/O set. Altium and Gerber files for both are on this page.

Connectors. Both Pucks mate through two connectors and both must engage together. On the P4-16 the alignment reference is the small connector, J1; on the P4-37 it is J2. Take the part numbers, pin assignments and connector positions from the datasheet for the model you are designing for — the P4-16 and P4-37 do not share a footprint.

Bus voltage.

- P4-16 — 12–48 V operating, 60 V peak

- P4-37 — 12–160 V operating, 200 V peak

Logic power is a separate 12 V rail, and it should be stable and robust. Keeping it independent of bus power is the point: it lets you drop VBus and disconnect motors while keeping communication to the Pucks alive. Design it as its own supply rather than deriving it from the bus.

Motor phases. Rate the phase routing for the currents your application actually draws — copper weight and trace width follow from that, not from the reference boards.

Clearance under the Puck. The P4-16 needs a clear keep-out under its footprint — nothing beneath it. The P4-37 sits about 4 mm above the board, so low-profile components can be placed underneath it.

Decoupling and bulk capacitance are optional, and useful at high power for filtering noise and tying into chassis.

Before you fab, re-check every pinout and connector position against the datasheet. The reference designs are a starting point, not a specification.

Mainboard Design

Where a MIB mates one Puck to one motor, a mainboard is the system-level board: it distributes bus power, supplies logic power, and hosts the CAN bus that ties every Puck to your host controller. On a small system the two can be the same board — the P4 Dev Board is both.

Start from the P4 Dev Board. The Altium and Gerber files are on this page, and it is the reference for power supply design.

Bus power. The mainboard handles all power distribution, so size it for the application — the phase currents your motors actually draw, across every Puck in the system. Rate each output for the Puck it feeds:

- P4-16 — 12–48 V operating, 60 V peak

- P4-37 — 12–160 V operating, 200 V peak

Logic power is a separate, stable 12 V rail. Budget roughly 0.5 A per Puck. Keeping it independent of VBus is what lets you cut motor power while communication to every Puck stays up. The Dev Board shows one way to build it: an on-board regulator derives 12 V from VBus, and when an external 12 V supply is connected it senses that and shuts down, so either source works with no switch. The regulator needs at least 12 V in to start.

Consider including a bus enable circuit. Being able to connect and disconnect bus power at the mainboard is the other half of the separate logic rail —together they let you drop motor power on demand while every Puck stays powered, on the bus and reachable for communications.

CAN. The mainboard is the central hub for every Puck on the bus, up to 31 of them, daisy-chained. Each Puck needs a unique CAN ID before it joins, or you will face communication errors. The Pucks communicates over CANopen — see the CANopen User Manual and the Electronic Data Sheet.

Terminate the bus with. Contact Barrett support for help with CAN termination.

Before you fab, check pinouts and connector positions against the datasheet for every Puck model in the system.