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 :)
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?
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.
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.
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 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. 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.
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 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 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.
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.
“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!