4Axis Break out / Multi-Purpose PCB build instructions:
This page documents construction as a break out board for up to 4
THB6064AH,
Linistepper, SLAm
or other PMinMO^ drivers. There are many
options for this board, and
not all relate to this use.
As a break out board, most users will be interested in the following options:
DB25 connector at the top for connection to PC Parallel
port for operation of stepper drivers via
TurboCNC
, Mach 3, or
EMC. Pin headers also support connection to
white board, or use as an Arduino "Shield" board.
4 Axis Header: Low cost ribbon cables (from underneath)
which terminate in standard
PMinMO
plugs^ at the drivers.
Pulse / Demo / Test option which replaces the PC as
the normal source of control signals with a simple variable speed STEP pulse
generator and DIRECTION control to demonstrate motor operation and test
drivers.
Up to 4 switches (can be limit switches or tactile switches)
and a pull up ("RP1") for them so the parallel port can be used to read
them.
Space for axis step indicator LEDs, on board PIC for intelligent test and
control, serial interface, over current and temperature sensors.
Most people will want to use the
4Axis board to support a stepper motor driver. Click block diagram for
larger version.
Click schematic for larger version in a new window.
There is also a google spreadsheet that shows the combination of connections
and helps clarify why they were setup as they were
^ Changes between version 4-5 and version 6 are indicated
in green
Don't let the schematic scare you! Pretty much the entire top half are items
that will probably not be used, but were easy to work into the PCB for
future expansion, we can ignore
them for now. The only important bits are the power regulator in the bottom
left, the STEPPERS header just above it which cables out to 4 stepper drivers
(e.g.
THB6064AH, Linistepper
or SLAm) and the DB25 connector to the
right which feeds those drivers from the PC
parallel port. The nStrobe signal
(see just below and right) drives a relay with LED indicator if you like.
RP1, on the right edge, mid way down, pulls up a set of 4 switches which
can be installed on the PCB as stop/jog switches or can be wired to limit
switches or any other connect to ground switch for feedback to the PC. Combining
all these functions on one printed circuit board was more cost effective
than making multiple different boards, but you may not wish to populate all
the parts of the board; To make different configurations easy, we sell each
option as the separate kit of parts:
Two Layer, plated through holes, silkscreen, soldermask
1
The printed circuit board only:
416036
J3
DB25, Female, Solder tail
1
DB25 pushes on to edge of PCB
CBL
DB25, Male-Male
1
Cable to connect to PC Parallel Port
416016
U1
PIC12F675, DIP 8
1
PIC Microcontroller & optional socket
R4
10K TRIM(w/ bail clamp)
1
Turn one way to step fwd, the other to step back
LEDS
T1, RED/YELLOW
2
LEDs show step and direction
RP1*
RP2*
1K, CARBON, 1/4 WATT, AXIAL
3
Couple Step/Dir to LEDs and pull up for switch. Supplied as single
resistors, not networks.
S4
TACTILE SWITCH AND COVER
1
Hold to start continuous pulse, quick push for single, long push for
burst
416025
U2
LM-7805 or LM-317, TO-220
1
Regulator
R6
1K Ohm, 1/8 WATT,
1
(For LM-317, not used with LM-7805)
R7
330 Ohm, 1/8 WATT,
1
(For LM-317, not used with LM-7805)
J4-6
3 Pin, 0.2" spacing
1
Terminal Block
D6
1N4001, 1A, AXIAL
1
Reverse protection diode
C4
470-1000uF, ELEC, 0.2 RAD
1
Main supply filtering (rated above supply voltage)
C5
10uF, ELEC, 0.1 RAD
1
Main output filtering
C6
100nF, CERAMIC, 0.1 RAD
1
Secondary output filtering. 22nF supplied.
R5
330 Ohm, 1/8 WATT,
1
Drives indicator LED
D9
LED, T1, GRN
1
Power indicator light
416068
Q1
TIP-122, TO-220
1
Darlington Power Transistor
D8
1N4001, 1A, AXIAL
1
Back EMF protection diode
J7/8
2 Pin, 0.2" spacing
1
Terminal Block
C8
~100nF, CERAMIC, 0.1" RAD
1
Ring prevention capacitor
R2
2.2 K Ohm, 1/8 WATT
1
Signal connection, current limit resistor
D7
LED, T1, YEL
1
Indicator light
R3
330 Ohm, 1/8 WATT
1
Drives indicator LED
416014 This
cable is pre-wired for the connector
on the Linistepper v2, SLAm and other
PMinMO^ compatible drivers.
General Guidelines for Assembly
All the reference designators (e.g. R3, J1, S1) are marked on the PCB
as close to pin 1 of that part as is possible.
Square Pad: Pin 1 of a chip or header, or the positive, long, lead on
a polarized component always has a square pad.
The assembly documentation is listed here in the order that the kits should
be assembled assuming ALL the options are being installed. Skip the sections
you don't want, but be sure to assemble in the order presented here: The
order of assembly is important as some parts can not be installed after
others.
FRONT
TOP edge
BOTTOM edge
BACK
TOP edge
BOTTOM edge
Soldering
When soldering, use a sharp tip and as high a heat as possible. The solder
should be standard flux core and as fine as possible. Hold the solder at
the point where the lead and the pad on the board meet, then apply the (just
cleaned) iron to the other side, again, at the point were the lead and the
pad meet. Ensure there is solid contact between the solder and both metal
parts, as well as the iron tip and both metal parts. A slight grinding or
twisting motion of the iron can be helpful. As soon as the solder melts,
or in a few seconds if it doesn't, remove the iron and allow the joint to
cool as long as possible. When soldering multi-lead parts like the PIC chip,
ribbon cable header or DB25 connector, to avoid heat build up in the plastic
case, do NOT proceed in order, but rather always solder what would logically
be the coolest lead next. Stubborn points can be eased with a bit of flux
dispensed from the point of a pen or pin. See our
soldering
class for more.
The lowest cost option for connecting the 4Axis board to your PC parallel
port is to just take an existing, good quality parallel printer cable and
cut off the printer end, then ohm out the wires to find the
Data D0-7 signals (pins 2-9 on the PC
connector) and strip/solder those wires directly into the holes labeled
D0-D7 on the bottom of the 4Axis PCB.
Of course, It's a lot quicker to solder on a DB-25 connector and use a parallel
extension cable. This connector MUST be a female connector. The cable used
from the PC parallel port should be a straight through, male to male as provided
in the PC parallel port kit option. The DB 25 connector is pressed onto the
edge of the PCB and positioned starting from one corner. Be sure that the
pins aline with the pads (it will only align one way) and then work one end
on, and slowly rock back and forth to spread the rest of the pins until the
PCB edge is fully pressed against the plastic of the connector. Check the
pins for alignment to the pads, both top and bottom and re-position as necessary.
DB 25 connector assembly
The picture below shows the back (bottom) of the PCB, as the DB25 connector
is being pushed into place. The row of pins under the solder pads is marked
with the signals from the DB25 as they relate to the PC parallel port. The
D pins are driven by the PC, and the direction of the other signals is indicated
with a little half arrow next to the name.
Note: +5 and ground were added and a very slight extra
space introduced between D6 and D7 so that the holes could be used with the
Arduino controller. This, along with J11 and J12 on the opposite edge of
the board, make it an Arduino "Shield".
The next picture, below, is the front of the PCB, and the row of pins under
the solder pads is marked with the signals from the DB25 as they relate to
how they are used by the drivers and this break out board. Solder each
pin, with the iron touching the end of the pin and the pad both at the same
time, and the solder fed from the side, near the body of the connector.
Note: The "En X", "En Y", and "EnZA" each connect to outputs on the
PC parallel port so that the drivers can be dropped into low power hold when
not in use. It requires a little extra setup in your CNC program, but it's
worth it for the temperature control on your motors and drivers. If
you really don't want to use those pins, you will need to cut the traces
for the enable lines. I've added little circles on these pictures to highlight
the marks on the PCB showing good points to cut. There is one in the upper
photo in the lower left corner, then two in the lower photo; one under "Z"
"STEP", and the other below "EnZA". If you don't configure the lines, make
sure your drivers are getting the correct signals. The Linistepper will pull
this line low automatically, but the SLAm will put it high (into low power)
by default so you will need to ground the enable line on the driver or here
on the board.
The Power kit provides regulated +5V supply for the divers internal use and
for the local options from an unregulated DC power source such as the motor
power supply. If your motor supply is more than +12V, or if you are running
more than one axis driver, you should probably add a heatsink (it doesn't
take a big one) as the regulator may get hot and shut down.
You could replace the LM7805 with a switching regulator like the Murata
OKI-78SR-5/1.5-W36-C
which can take up to 36 volts and still provide 1.5 amps at 5volts.
The version 6 board provides support for the new LM317 kit in place of the
7805. This allows higher motor voltages (up to 50 volts) with a good
heatsink or small CPU cooler (heatsink with fan)
Version 5 LM7805 regulator on front
Version 6 LM7805 regulator on front
Version 6 LM317 regulator on back.
Only LED, D6, and terminal on front.
Assembly is easy: Most of the components can be mounted from the front or
the back of the board. Think about what you want before you start. Mounting
on the bottom leaves the front clean for terminal blocks and switches, but
requres extra space between the board and the mounting surface.
Mount the diode, D6, first. The end with the band goes in the square hole.
Ensure the power regulator, U2 for the LM7805 or U4 for the LM317, is in
as shown on the solder mask; with the back to the outside of the PCB when
inserted from side where the chip outline is printed. If you run more than
one or two axis, you may need a small heatsink. Take care not to cause a
short with solder... the holes are very close together.
Be sure to mount the electrolytic capacitors C4-5 with the positive lead
in the hole closest to the "+" outside the circle. The positive lead is the
one farthest from the stripe on the side of the cap. The big 1000uF cap,
C4, can be mounted either on front or underneath.
The long lead of LED D9 needs to be in the square hole toward the resistor
R5. The resistor is installed upright; with one lead straight down through
one hole and the other bent around and back down through the other hole.
If using the LM317 regulator, install R6 and R7, the 1K and 330 ohm resistors.
Solder the terminal which replaces J4, 5 and 6 on last.
The driver works by grounding the COIL- lead. If you are using a relay with
a +5 volt coil, its other lead can be connected to COIL+, which connects
to the regulated +5 line. Be sure your +5 supply can handle it. A higher
voltage coil can be accomodated by just connecting the other relay lead to
an external supply (e.g. +12 or +24 volt) and installing D8 directly across
the coil leads. Whatever you do, don't leave D8 out! Reverse EMF protection
across the relay coil is critical.
Start by installing D8, either on the PCB or directly across the relay coils.
The end of the diode without the stripe connects to COIL- in all cases, and
the end with the stripe, to the other relay coil lead, usually COIL+.
The TIP122 driver, Q1, can be installed on top or bottom of the PCB, just
make sure the pins are in the correct holes. See the part outline in the
silkscreen on the bottom.
The LED installs in the little circle just under the Y in RELAY on the front;
long lead in the square hole. The other components, R2, R3 and C8 are
pretty easy, and can be installed on the back or front. The resistors are
standing, with one lead directly in, and the other bent over and looping
back down alongside the first.
Leave the terminal blocks for last, and as always, try to work from the center
of the board out to the edge.
Before you do this part, make sure you have soldered
in the +5 power option and the relay driver as they have components that
end up being very close or under JP3.
Solder the IDC header JP3 in place on the bottom of the PCB. Pin 1
is clearly marked on the PCB, but harder to find on the header; look for
the faint "V" embossed on the side of the header shroud pointing to pin one.
The polarity notch should be opposite the DB25 connector. The ribbon cable
may not have a polarity nub to match that notch but the red stripe should
still be on the pin 1 end and there is another of those very faint "V" symbols
embossed above pin one on the connector.
It turns out that not only is it very difficult to see that
"V", it's just about impossible to get a picture of it; the "V" is right
there, but totally invisible in this picture. At least the picture shows
the correct orientation
Note for Arduino users. If you want to mount the BOB to an Arduinio,
there really isn't room for this cable on the underside of the BOB. You
can mount it on the top, just make sure you also mount the
PMIMO connectors on the stepper motor drivers on the bottom of thier PCBs
as well. Pin 1 will now be GND, and pin 2 will be X-Enable. Be carefull...
check the connectivity before power on.
The other end of of the cable is divided into 4 PMinMO 2x5 connectors
This option drives 3 of the Axis without a PC. It is designed to
demonstrate stepper motor control, and test the drivers and motors with a
known good signal. Note that this option can NOT be used with the
PC option: The board must be build as a PC interface, or a demo/test board,
not both. The step and direction signals are developed by a PIC12F675 which
is supplied pre-programmed. Because the chip has limited IO, only 3 axis
are driven, and the A STEP signal is used as the DIRECTION signal for the
other three axis.
Because of minor changes between the Version 5 and 6 PCBs, the PIC supplied
with this option must be programmed to match the board. If you purchased
them together, no worries! If you order this option seperately, please specify
the version of the PCB.
Operation: The motors turn one way or the other as you rotate the
knob of the pot. As you turn it away from center, nearer either end, the
motors will step faster and faster. Turning back from that limit toward the
other, the motors will slow, reverse, and then speed up again in the opposite
direction. One LED shows the direction of rotation, the other shows the rate
of pulses.
Assembly:
Start with two 1K ohm 1/8 watt resistors installed in the last two positions
of RP2; between A Step and the A LED, and Z STEP and the Z LED. When
you clip off the extra length on the leads, keep them! You will use
those to bridge JP4 and JP5, A STEP to all the direction lines, and two pins
of J12 (between A2D and ADJ)
Locate J12 on the bottom edge of the front of the board. Bend on of the resistor
leads you saved in half and use it to connect pin 3 of J12 ("A2D") to pin
4 ("ADJ") as shown here:
Bend another extra lead length in half and insert
it between the holes of JP4, and solder it in place, then clip and discard
the remaining length. Repeat for JP5.
You can choose to use or ignore the IC socket. If you use the socket, you
can remove the PIC and the A STEP to XYZ DIR jumpers and still connect the
board to a PC in the future: Never both install the PIC and jumpers and
connect to a PC at the same time! Note that the PIC is installed on the
back (bottom) side of PCB. Place and solder the socket or the PIC12F675
pre-programmed chip in the highest position of U1 with the notch on the end
toward "U1 PIC". The little dimple on the top of the PIC is nearest pint
1 and should be installed so it is in the square pad, nearest JP5 . Take
care to avoid overheating the chip; don't apply heat for more than a few
seconds on each lead and solder the leads in a cris-cross pattern, allowing
time for each pin to cool before you solder the next closest pin.
Looking at the back of the board, upside down, with the DB 25 pads at the
bottom and J11 / J12 at the top, look just to the right of the PIC U1, and
find C7 (upside down "C7"). From the round pad of C7 (the one farthest from
JP5), move one pad to the right. On the ver6 PCB, this pad is marked as "A3".
Jumper that pad to the "S1" pad just below it as shown in the picture.
Install the ~1K ohm (BRN, BLK, RED) resistor between pin 1 and pin 2 of RP1,
"S1" to "Vcc" (normally a network resistor, but since we are only using one
switch, supplying a single resistor allows us to keep the cost of the kit
down), and install the switch in the S1 position.
Install the LED's which will show direction and step signal. When you
clip off the extra length on the leads, keep them! You will use those
to bridge the X, Y and Z DIRECTION signals to the A STEP signal, as described
a little later on.
The LEDs can be installed in two different positions depending on the type
of display you like: If the direction LED (installed on the "A" step indicator
near the pot) is installed between the square pad (long lead) and the next
pad towards the pot, it will light when the motors are going forward, and
go out when they turn reverse. In the picture below, the LED on the
right is being inserted in that way; long lead in the square hole, short
lead pointed to the hole it will fill. If you install it in the pads with
the silkscreened circle and the little picture of an LED, it will do the
opposite. In either case, the long lead must be in the hole furthest from
the pot. The STEP LED is installed on the opposite end of the board, in the
"Z" step indicator near U2. If you install it with the long lead in the square
hole, the LED will be out most of the time, and flash briefly with each step
pulse. If installed in the circle, it will be one most of the time, and blink
out briefly with each pulse. In the picture below, the red LED on the left
side is being installed in this manner. Again, the long lead must be in the
hole farthest "up" the board.
The potentiometer goes on top of the schematic symbol of a variable resistor
on the right side of the board, viewed from the front. See the picture above.
Because the shaft can be a little hard to turn, we include a "bail lock"
which can be screwed onto the shaft for a better grip. Hold the two brackets
"spooned" with a clearance hole adjacent a threaded hole and start both screws.
Slip the bail lock over the white shaft of the pot and tighten the screws.
Using the excess leads from the LED's you saved above, jumper the A STEP
to X DIR and Y DIR to Z DIR at the top edge of the front of the PCB then
jumper X DIR to Y DIR just left of the resistors as shown below. If you would
like one motor to always turn forward, you can leave out a jumper. Leave
these sticking up a bit so you can clip them if you decide to connect to
a PC in the future. Don't connect the board to a PC parallel port while
these jumpers are installed, that would short the port pins together and
might burn out the port.
Once the pulse parts are installed, you can apply +5 volts via the holes
in the upper left corner of the board or by installing the +5
regulator option. The LED's should blink, then begin to operate. When
connected to drivers (probably by the Header/4 Axis
cable), the motors should begin to turn as you move the pot. When the
potentiometer is perfectly centered, it will not pulse at all, so if you
don't see a light, turn it left a bit and try again. Right of center, the
direction will be low and it will step faster and faster as you reach the
limit. Left of center will step in the opposite direction, again, faster
as you reach the limit. Pushing the button once should stop the pulsing,
then each quick push should step once. Push a bit longer for a burst of pulses
and hold the button until the light stays on, then release it to re-start
continuous pulsing. Here is a picture of the finished pulse / demo / test
unit with the +5 regulator option in operation:
Although a kit is not yet available, you can add limit switches by installing
RP1, a 1K to 5K ohm, SIP resistor network (bussed, not isolated) with 5 or
more pins. Jameco part 267910 is fine. The pin with the dot goes in the square
pad, and if there are more than 5 pin, cut off the extras or just snap the
resistor as shown in the picture. The little blue 2 pin headers (Jameco 152347)
are optional if you can solder your wire directly into the pads, but they
really make it easy for larger wires like the standard ZIP cord used here.
Almost any micro switch will work, as long as you can solder your wires to
the switch terminals. Here is each switch and the parallel port pin it connects
to.
The switches act by grounding the pin, while RP1 tries to pull
the pin up to +5 volts. The direct connection of the switch can always overpower
the resistor, so the result is ground when the switch contacts meet and +5
when they are open.
I have the Linisteppers V1 for many years and it is the time to use them.
Can I use the 4 Axis V5 board? If yes how I should connect them? James
Newton of MassMind replies: You can use the 4 axis board, but you
will need to build a custom cable between the 4 axis board and the Linistepper
version 1 because the pinout is different. See the documentation for each
and just connect the signals. Step to Step, Direction to Direction, etc...
If you aren't using the other features of the 4 Axis PCB, such as the relay
driver, switchs, LEDs, or 5V power supply, it might be just as easy to cut
off a parallel cable and wire it directly to the Linstepper
V1's.
Since there is no available kits for the relay driver, is it possible to
get a parts list at least? James
Newton of MassMind replies: Based on your feedback and others, we've
added a relay option kit and parts list. For the parts list, just scroll
up to the "Options" listing and then to the bottom of that
section.
Comments:
Values of R6 and
R7 for the voltage regulation are reversed on the schematic (correct on the
parts list). Results in 5v being low.
Your board layout, service, and quality are awesome!!!! Thanks,
Nathan
James
Newton of MassMind replies: Ah, thank you for noticing that! I've
fixed it now.
416014 This
Before you do this part, make sure you have soldered
in the +5 power option and the relay driver as they have components that
end up being very close or under JP3.
It turns out that not only is it very difficult to see that
"V", it's just about impossible to get a picture of it; the "V" is right
there, but totally invisible in this picture. At least the picture shows
the correct orientation
Assembly:
Bend another extra lead length in half and insert
it between the holes of JP4, and solder it in place, then clip and discard
the remaining length. Repeat for JP5.
