Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Turns out that the anonymous parallel port breakout board isn’t compatible with an optoisolated stepper driver: each output has a 1 kΩ series resistor that limits the current well below the driver optocoupler’s expectations. The driver has an internal 300 Ω resistor on each input, too, which doesn’t help in this situation.
A detailed look at the resistors lined up in front of the connectors:
Anonymous parallel breakout board – series resistors
The breakout board would work fine with non-isolated drivers, like the Pololu breakout boards, so it’s not really at fault. The fact that there’s no doc anywhere to be found means you (well, I) couldn’t discover this without buying it first, but … I suppose it’ll come in handy for something.
One could short across the resistors, but I intended to use this board for the initial bringup and all that soldering defeats the purpose.
Parallel port breakout boards of this ilk run about $14, complete with cable, on eBay:
5 axis parallel port breakout board
The PCB has no part number and the inferred URL isn’t productive. The “driver CD” accompanying it has doc for every possible board the vendor might sell and, absent a part number, the file names aren’t helpful. An exhaustive search suggests it corresponds to the HY-JK02-M 5-axis interface board manual.doc file.
Despite any implication to the contrary, the board does not have optoisolators between the parallel port pins and the outside world. The stepper driver bricks should, but the input signals from limit switches and suchlike connect directly to the guts of your PC.
This overview (from the manual) shows the physical pin layout (clicky for more dots) and reveals the hidden silkscreen legend:
HY-JK02-M Breakout Board – overview
It looks like the board I got added a spindle relay driver transistor, plus a few resistors over by the manual control connector on the right.
Notice that the fourth terminal on each axis is GND, not the positive supply required for the optoisolators on the 2M415-oid driver bricks, which means you can’t just run a section of ribbon cable from the breakout board to the brick. You’ll need a separate +5 V (or whatever) power supply wire for each brick, with a common return to the system ground for this board. Those terminals are firmly bonded to the top and bottom ground planes on the board, so there’s no practical way to re-route them.
The small switch in the upper left, just to the right of the parallel port connector, selects +5 V power from the USB port (which has no data lines) or the power connector in the lower left. The LED near the switch won’t light up until you have both the parallel port cable and the USB cable plugged in.
The doc includes a timing diagram with no numeric values. I established that it can’t keep up with a 500 kHz pulse train and seems content at 100 kHz, but that’s conjecture. Setting the timing to match whatever the stepper driver bricks prefer will probably work. The diagram suggests the setup and hold times for direction changes are whatever you use for the minimum time between step pulses.
This shows the functional labels:
HY-JK02-M Breakout Board – function labels
The parallel port connector output pins, sorted by function:
Pin
9
1
2
14
16
3
7
8
6
5
4
17
Function
Spindle
motor
Enabled
X step
X dir
Y step
Y dir
Z step
Z dir
A step
A dir
B step
B dir
The parallel port connector input functions, sorted by pin:
X -Limit
Y- Limit
Z- Limit
A- Limit
Emerg Stop
10
11
12
13
15
The table uses Chinese for Pin 15: 急停.
It’s not clear whether the pins on the manual control connector are inputs or outputs, nor what the three separate Enabled lines do:
P1
P2
P3
P4
P5
P6
P7
P8
P9
P10
P11
P12
P13
P14
P15
B step
B dir
A dir
Z step
Y step
X step
X dir
Enabled
5V/VDD
5V/GND
A step
Z dir
Y dir
Enabled
Enabled
The three white connectors in the middle drive an LED readout board that’s probably most useful as a DRO for CNC-converted manual mills using the pendant for positioning.
The small white connectors duplicate the functions of the green screw terminals. They’re probably useful in a small machine that I’m not building.
This isn’t the board I intend to use in the final setup, because I need far more I/O pins, but it’ll serve for the short term.
Collected from various spots around the Web, including evanescent eBay listings, and reformatted to make sense, these specs describe the 2M415 stepper driver: a smaller sibling of the 2M542 family.
Blurb
+15 to 40VDC Supply Voltage
H-Bridge, 2 Phase Bi-polar Micro-stepping Drive
Suitable for 2-phase, 4, 6 and 8 leads step motors, with Nema size 16 to 23
Output current selectable from 0.21 ~ 1.5A peak
Compact credit card size package
Optically isolated single ended TTL inputs for Pulse, Direction and Enable signal inputs
Selectable resolutions up to 12800 steps
Over Voltage, Coil to Coil and Coil to Ground short circuit protection.
Electrical specs
Parameters
Min
Typ
Max
Unit
Output Current (Peak)
0.21
–
1.5
Amp
Supply voltage
15
36
40
VDC
Logic Input Current
7
10
16
mA
Pulse input frequency
0
–
200
KHz
Low Level Time
2.5
µsec
Mechanical specs
Cooling
Natural Cooling or Forced Convection
Space
Avoid dust, oil, frost and corrosive gases
Ambient Temp
0 °C – 50 °C
Humidity
40 – 80 %RH
Vibration
5.9 m/s² Max
Storage Temp.
-10 °C – 80 °C
Weight
Approx. 150 gram
Dimensions
2M415 Footprint
Wiring diagram
2M415 Wiring
Notice that the driver requires a positive voltage for the optoisolators.
Of course, the box from halfway around the planet contained HB-415M drivers. Should you go looking with the usual keywords, you’ll find that HB-number turns up mostly “House Bill number” citations from various state legislatures. Popping the top off the drive reveals www.sikesai.com, which eventually produces a description and PDF datasheet for the driver. It turns out to be an “Ultra Low Noise” driver, whatever that means, with reasonably standard specifications that correspond more-or-less to the 2M415 drivers I thought I was getting.
Being in the market for some more-or-less industrial stepper driver bricks, here’s a summary of what’s currently available on eBay from the usual vendors, copied-and-pasted directly from the descriptions with some fluff removed:
M542 Stepper Driver Board Controller
Supply voltage from 20V DC to 50V DC
Output current from 1.0A to 4.5A
Self-adjustment technology, full to half current self-adjustment when motors from work to standstill via switching off SW4
Pure-sinusoidal current control technology
Pulse input frequency up to 300 KHz
TTL compatible and optically isolated input
Automatic half-current reduction as long as switching off SW4 when motors stop
16 selectable resolutions in decimal and binary, up to 51,200 steps/rev
Suitable for 2-phase and 4-phase motors
Support PUL/DIR and CW/CCW modes
Short-voltage, over-voltage, over-current and short-circuit protection, protect the PC, motors, driver etc from being damaged
M542H Stepper Driver Board Controller
Supply voltage from 20V DC to 100V DC
Output current from 1.0A to 4.5A
Self-adjustment technology, full to half current self-adjustment when motors from work to standstill via switching off SW4
Pure-sinusoidal current control technology
Pulse input frequency up to 300 KHz
TTL compatible and optically isolated input
Automatic half-current reduction as long as switching off SW4 when motors stop
16 selectable resolutions in decimal and binary, up to 51,200 steps/rev
Suitable for 2-phase and 4-phase motors
Support PUL/DIR and CW/CCW modes
Short-voltage, over-voltage, over-current and short-circuit protection, protect the PC, motors, driver etc from being damaged
2M542 Stepper Driver Board Controller
Suitable for 2-phase hybrid stepper motors (Outer diameter: 57,86mm)
H bridge bipolar constant phase flow subdivision driver
In round numbers, the M542 seems to be the basic driver for NEMA 17 / 23 /34 steppers. Remember that current isn’t proportional to frame size.
The M542H has a higher voltage limit that may be more useful with larger / multiple-stack motors; higher voltage = higher di/dt for a given inductance = same di/dt for higher inductance.
The 2M542 seems to be slightly different from both of its siblings: higher minimum voltage, slightly lower maximum current, slower step frequency. Many of the listings apply both M542 and 2M542 to the same hardware in the same listing, so it’s not clear what you’d get in the box. Ask first, trust-but-verify?
The MA860H seems appropriate for NEMA 34 / 42 and up , due to the much higher minimum current.
The 2M420 seems to be intended for NEMA 17 /23 class steppers. It’s not available from nearly as many suppliers.
The 2M982 looks like another NEMA 34 /42 and up driver.
The DM1182 seems strictly from industrial, but if you don’t know what you need, it’s a do-it-all killer.
As with all eBay listings, the picture need not match the description and neither may match what actually arrives in the box from halfway around the planet.
The Smell of Molten Projects in the Morning 