That’s why we test

The testing protocol of IONI drives is derived from Argon test setup and consists several steps including:

  • Chip programming and program verification
  • Testing of digital inputs & outputs
  • Testing accuracy of analog inputs (analog setpoint input as well as on-board sensor signals)
  • Testing interconnectivity of internal circuity
  • Testing all electrical functionality (such as safe torque off)
  • Burn-in testing with maximum load. The load is a large stepping motor which utilizes all four power stage channels.
  • From burn-in data, we measure time versus heating (efficiency) and torque control behavior
  • All results, data and logs are stored in SQL database where we can look for anomalies if a device fails later
IONI with one "tombstoned" 0604 size resistor

This is a reason why we test. IONI with one “tombstoned” 0604 size resistor, that would have been hard to spot without testing.

80/20 law

The Pareto’s principle has been shown true once again. It says that 80% of work comes from 20% of remaining things. The last two weeks have been so busy finishing & perfecting IONI that I had barely time to eat properly or check emails. Luckily 2 weeks ago we were not at 80% but 99% so that 2 weeks was enough to fill the missing 1%. This reminded me why I don’t like to promise any fixed dates but rather say “when it’s ready”.

Today finally the firmware and testing rig has been finalized and frozen. First set of devices are now tested and the shippings begin on Friday. Next up: the user guide :)

Short circuit test

Testing IONI servo motor drive short circuit ruggedness. Drive supplied with maximum voltage and spinning a 1 kW motor maximum speed while it’s being short circuited (it’s the worst case scenario).

Spoiler: it does not break.

Adaptive current limit

We have been experimenting with adaptive current limit on IONI prototypes. This means there isn’t fixed specifications saying how much current drive outputs continuously and peak but there is just one specification: maximum. Drive will allow maximum output if it runs cool enough and will start throttling down current if temperature rises beyond certain level. This means, if you cool it well, you will get lots of power.

So far it seems to be working very nicely! See the video below.

As we were now able to push prototypes to their limits without worrying to break the only units, it turned out that we have been underestimating them! Without cooling it seems to output approx 9-10 Amps and with cooling 15 Amps (actually it could go higher but the lab power supply ran out of juice). What do you think about this?

Something completely different – Laser diode driver!

Along motor controllers, we have been designing a laser diode driver. Laser diode driver, or LDD, is basically a current regulator that is used to drive constant or pulsed current to a semiconductor diode that emits laser light.

Intensify Nx50 laser diode driver delivers continuous current of 50 A at exceptional 95% efficiency.

Intensify Nx50 laser diode driver delivers continuous current of 50 A at exceptional 95% efficiency.

The story behind this is the fact that I have been working close to laser diode industry where I get understanding of how laser diodes are utilized and controlled, as well as expertise of precision current control from motor drives. Combining these two makes it almost trivial to make a new kind of LDD that has never seen before.

Intenisify Nx50 laser diode driver delivers up to 150 A continuous current when three boards are connected parallel by stacking

Three Nx50’s stacked forming a 0 – 150 A driver.

The product is now finished and it’s called Intensify Nx50. It has unique ability to be stacked to increase output rating. Single board outputs current between 0 – 50 A and voltage between 0.8 – 5.0 V. Two of them output 0 – 100 A / 0.8 – 5.0 V and three 0 -150 / A 0.8 – 5.0 V etc.

Funny observation from testing of 150 A driver in pulsed mode is that the thick cables tend to physically move due to magnetic force generated by flowing current. When current flows in parallel conductors in opposite directions, cables repel each other. It takes hefty amount of current to feel and see it :)

ION development progress

ION development has been very active in the last 2 weeks. Last achievements are the implementation of ADC readouts and power stage control. Both were discovered to have some schematics & layout errors, but that’s why people make prototypes.

Ion development rig as it exists today

Ion development rig as it exists today. Tiny jump wires on ION board have appeared.

After fixing the issues by PCB trace cuts and jump wires, the drive seems fully healthy. ADC readout of phase currents seems to perform well with extremely low noise and power stage seems to exceed the initial capability calculations. At the moment power stage temperature is 63 degrees Celsius while it outputs 8 A continuous current to the stepper. Some air flow is present from the fan behind the motor.

The very first ION servo drive

Good news! The very first fully assembled ION servo drive boards have arrived. I jumped straight to programming the thing. Few parts of code have been already ported from Argon and everything has worked flawlessly so far.

The very first ION board fully assembled in its creator's hand

The very first ION board fully assembled in its creator’s hand

The drive is equipped with ARM Cortex M4 processor with hardware floating point unit (FPU). I ran small test of FPU performance and found out that simple floating point arithmetic operations execute 20-30 times faster compared to non-FPU code. This means, all control code can be written with floating point math yielding ultimate precision and dynamic range without sacrificing servo bandwidth.

More brushless AC servo motors

More brushless AC servo motors arrived today from a different manufacturer than the previous ones. These ones have premium build quality, high power density (compact size versus power) and reasonable pricing. Such sweet ingredients make a very tasty candidate for our next stocked motor choice.

New motors, 400W and 600W models with brake and 2500 P/R encoders. Encoder cables are pre-made for Argon.

New motors, 400W and 600W models with brake and 2500 P/R encoders. Encoder cables are pre-made for Argon.

A good thing is, this manufacturer makes wire endings according to our specifications, so they plug direclty to the drive. Out of the box, the first motor was correctly set-up and running in less than 5 minutes. These irons spin silky smooth and quiet as expected.

The new motors under very first test

Servos under the very first test

Servo motor driven laser projector

To demostrate the use of SimpleMotion V2 library with Argon drives, we created a laser projector demo where the angle of two surface mirrors are controlled by two brushless servo motors and Argons.

This was the demo presented also in our SPS IPC DRIVES visit few weeks ago.

Some random project facts:

  • Motor powers are 100W and 300W continuous. Maybe it’s the most overpowered laser projector made.
  • The surface mirrors are cut from hard disk drive platters.
  • The smaller motor doesn’t have full smoothless any more as it was partially burned by accidentally swapping the motor cables causing too much current to it.

Argon testing procedure complete!

“If a thing is worth doing, it’s worth doing well.” That could describe the ideology behind the quality assurance procedure designed for the Argon drives. The testing hardware & software platform is now fully complete and I did already run the tests for the drives I have in my hands now. This means, drives are being now prepared for shipping!

There will be a dedicated post when items are placed to our web shop for ordering. It could be today or tomorrow!