I’m excited to announce the release of the newest moteus motor controller, the moteus-x1!
The biggest differences between the moteus-x1 and other moteus controllers is improved output phase current capacity. The x1 is rated for 25A continuous output phase current with no cooling and 60A continuous with fan based cooling. The other big improvement are 12V fan output pads with PWM support. Supporting high power cooling helps the x1 to achieve its higher output current rating.
We’ve got a new firmware release for the moteus controllers up on github now, 2024-10-29! This update has a few new capabilities, a brief summary is below, while more detailed posts will come in the not too distant future:
MA600 Support: The MA600 from Monolithic Power Systems is an absolute magnetic encoder that uses a TMR (precision tunnel magnetoresistance) sensor. It is much more accurate with less noise than the AS5047P that moteus uses (or the MA732).
It’s another new product day here at mjbots! Introducing the mjpower-ss:
This provides many of the same functions as the power_dist r4.5b:
Pre-charge: High capacitance, low-impedance loads up to 4000uF will be safely turned on in a controlled manner.
Undervoltage and overcurrent protection: If the instantaneous current exceeds 100A, a soft circuit breaker is engaged.
Connector multiplexing: 1x XT90 input feeds 6x XT30 output connectors which are wired in parallel.
External switch: An external illuminated switch is supported, with the same connector and pinout as for the power_dist. A switch harness can be purchased separately.
I’m excited to announce the newest addition to the moteus line of BLDC controllers, the moteus-c1! The moteus-c1 is a smaller, lower power, lower cost version of the moteus-r4 and moteus-n1, but still packs a big punch.
The top of the line performance metrics for the entire moteus lineup now look like:
| moteus-c1 | moteus-r4 | moteus-n1 | |
|---|---|---|---|
| Input Voltage | 10-51V | 10-44V | 10-54V |
| Peak Phase Current | 20A | 100A | 100A |
| Continuous Phase Current | 5A / 14A | 11A / 22A | 9A / 18A |
| Dimensions | 38mm x 38mm | 46mm x 53mm | 46mm x 46 mm |
| I/O | AUX1 D and E are present as through hole pads. AUX2 is identical to moteus-n1 | AUX1: SPI, Hall, ADC AUX2: I2C and UART 3.3V only | AUX1 and AUX2 support SPI, UART, Quadrature, Hall, and I2C. 5.5V and 3.3V provided on each connector. I2C pullups are configurable on each connector. |
| RS422 | None | None | Built-in transceiver for RS422 based encoders |
| CAN fault tolerance | 58V | 12V | 58V |
| Price | $69 | $79 | $149 |
The upshot is that for low current motors where RS422 is not required, it is nearly as capable as the moteus-n1 for less than half the price!
It continues to be the spring of new products at mjbots (see the mjcanfd-usb-1x from earlier), and today I have some basics that are newly added to the store to make building machines just a bit simpler.
First are two tiny boards to make daisy chaining power and CAN-FD connections easier for boards that don’t have built-in daisy chain connectors like the moteus-n1. First is a junction board for PH3 cables:
And the second is a similar junction board for XT30 cables:
When the moteus acceleration and velocity limits were first announced more than a year ago, it was noted that the semantics of using the legacy “stop_position” along with the new acceleration and velocity limits was “not particularly useful”. In the meantime, I’ve seen many cases where people get tripped up by this, even more so since developer kits now come with velocity and acceleration limits configured.
To mitigate that, as of firmware release 2023-09-26, moteus will now fault with code 44 if you attempt to use a stop_position while acceleration or velocity limits are configured. Here’s a quick reminder on how to upgrade:
I don’t normally post about moteus firmware releases, but there have been many in the last few months that fix some long standing bugs and regressions. First, the current release as of this post is:
With that out of the way, here some of the fixes:
It is embarrassing how long this issue has been outstanding, but ever since the flexible I/O system was introduced, there has been an issue where if the gear reduction was configured to a value other than 1, then the output position would drift from the source encoder over time. If control was not active, you would see the position drift, and if control was active, then moteus would report the correct position, but the actual position would drift.
This is a short and sweet post. The moteus-n1 as previously announced in beta form is now officially available at mjbots.com!
Here is yet another new product announcement! In the same line as the new pi3hat, here is a new minor revision of the power_dist, the r4.5b:
The changes are largely the same as for the new pi3hat:
The input voltage range is extended from 10-44V, to 10-54V.
The CAN-FD port has +-58V bus fault protection, up from +-12V.
Additionally, the measurement noise of the output current has been improved from 300mA to approximately 30mA.
Implied by my previous writeup on pin selection for external connectors, we’ve got a new variant of the moteus controller to announce today in beta form, the moteus-n1!
This variant is intended to be more feature-full, higher performance (and higher cost). Here are some bullet points of the biggest differentiators with r4.11:
| moteus n1 | moteus r4.11 | |
|---|---|---|
| Price | $159 USD @ qty 1 | $104 USD @ qty 1 |
| Size | As small as 46mmx46mmx8mm with optional back connectors omitted. 58% of the volume, 87% of the top down footprint size of r4.11 | 53x46x12mm |
| External Peripherals | Each of the auxiliary connectors supports SPI, UART, ADC, SW & HW Quadrature, Hall sensors, and I2C. 5V and 3.3V is provided on each connector to power peripherals (100mA for each voltage available combined between both connectors). I2C pullups are configurable on each connector. All 4 pins on AUX2 are 5VT, the two non-SPI pins on AUX1 are 5VT. | ENC (AUX1) supports SPI, Hall and ADC. ABS (AUX2) supports UART and I2C and are both 5VT. |
| RS422 | Built in RS422 transceiver for communicating with RS422 / BiSS-C encoders (BiSS-C / SSI not yet supported in software). | None |
| Voltage | 8-54V, 48V nominal | 8-44V |
| Peak Output | 100A output phase current, 1200W | 100A output phase current, 500W |
| Continuous Output | 9A output phase current ambient, 18A w/ thermal management | 11A output phase current ambient, 22A w/ thermal management |
| CAN fault tolerance | 58V bus fault tolerance | 12V bus fault tolerance |
| Power Connectors | Solder pads for DC bus input, one always present XT30, one optional XT30 | 2x XT30 |
The short form is that the n1 does not really expand the set of motors that can be usefully driven, but does enable operation in 48V systems, is more compact and electrically robust and provides significantly improved external peripheral support.
