Break Out / Multi-Purpose Board
This page is for Version 4 of our break out board. The new version
5 is here: 4axis5build. The old version is
here: 4axis3build
4Axis Break out / Multi-Purpose PCB build instructions:
This page documents construction as a break out board for up to 4
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. 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.
-
+5 volt regulator on the left (the big capacitor is installed
underneath in this picture)
-
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.
-
Relay coil driver on the top right with indicator LED.
-
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.
Mouse over the diagram below and click on the highlighted areas to find more.
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
^
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 LM7805 power regulator in the
bottom left, the STEPPERS header just above it which cables out to 4 PMinMO
driver headers (e.g. The Linistepper or
SLAm stepper drivers, and the DB25 connector
to the right of that which feeds those drivers from the PC
parallel port. The nStrobe signal
from the DB5 (see just below and right) drives a relay with LED indicator
if you like, and the RP2 resistor pack below that (right of the LM7805) and
the LED's in the lower right corner provide a visual indication of each step
(if you send a wide enough pulse from your CNC software). 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. Here are the instructions
for assembling each option on the board: Please note, the order of assembly
is important, as some components are difficult to reach after other components
have been soldered in.
Options: 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;
for example, if you run small 8 to 10 volt motors, a single ATX PC power
supply can provide both +12 volt motor supply and +5 volts for the linisteppers,
so the voltage regulator section would be redundant. To make different
configurations easy, we sell the kit(s) in separate parts:
Kit
|
Parts |
Specs |
QTY |
Description |
PCB: 416012 |
|
PCB1 |
Two Layer, plated through holes, silkscreen, soldermask |
1 |
The printed circuit board only: |
DB-25 PC Parallel Port kit: 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 |
Relay driver: #4Axis2RLY Not yet available.
|
| Pulse kit: 416016 |
|
U1 |
PIC12F675, DIP 8 (w/ optional socket) |
1 |
PIC Microcontroller |
|
R4 |
TRIM, 10K (w/ optional bail clamp) |
1 |
Turn the pot one way to step forward, the other to step back. Bail clamp
as handle. |
|
LEDS |
T1 |
2 |
LEDs show step and direction |
|
RP2* |
CARBON, 1/4 WATT AXIAL, 1K Ohm |
2 |
Resistors couple Step / Direction output to LEDs. Two resistors, not
a network. |
|
RP1* |
CARBON, 1/4 WATT AXIAL, 1K Ohm |
1 |
Pull up for switch. Single resistor, not a network. |
|
S4 |
TACTILE SWITCH AND COVER |
1 |
Hold to start continuous pulse, quick push for single, long push for
burst |
|
|
WIRE, ~3" |
1 |
Jumper switch to available PIC input pin. |
+5 Power kit: 416025 |
|
U2 |
LM-7805 |
1 |
5 Volt regulator |
|
J4-6 |
3 Pin, 0.2 |
1 |
Terminal Block |
|
D6 |
1N4001, 1A, AXIAL |
1 |
Reverse protection diode |
|
C4 |
ELEC, 0.2 RAD, 1000uF |
1 |
Main supply filtering |
|
C5 |
ELEC, 0.1 RAD, 10uF |
1 |
Main output filtering |
|
C6 |
CERAMIC, 0.1 RAD, 100nF |
1 |
Secondary output filtering. 22nF supplied. |
|
R5 |
1/8 WATT, 330 Ohm |
1 |
Drives indicator LED |
|
D9 |
GRN LED, 0.1 RAD, T1 |
1 |
Power indicator light |
The cable:
 416014
This cable is pre-wired for the PMinMO connector on the Linistepper Version
2, SLAm and other PMinMO compatible drivers. Single 40 pin 28AWG ribbon cable
with 4 IDC connectors and shrouded PCB header
|
|
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.
Pin 1 almost 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.
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.
Option Assembly Instructions
| 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 3-9 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. These
are provided in the PC parallel port kit option. The DB 25 connector is pressed
onto the edge of the PCB. It is positioned starting from the corner of the
PCB. 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. Also: Setup instructions for
Mach3, |
| Driver |
PC PP |
| XStep |
Pin2 D0 |
| YStep |
Pin3 D1 |
| ZStep |
Pin4 D2 |
| AStep |
Pin5 D3 |
| XDir |
Pin6 D4 |
| YDir |
Pin7 D5 |
| ZDir |
Pin8 D6 |
| ADir |
Pin9 D7 |
| Relay |
Pin1 nStrobe |
| X en |
Pin14 |
| Y en |
Pin17 |
| Z&A en |
Pin16 |
|
| |
Note: This is the back of the PCB, and 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 driving by the PC, of course, and the direction
of the other signals is indicated with a little half arrow next to the
name.
+5 and ground were added and a very slight extra space introduced between
D6 and D7 so that the holes could be used as a header for the Arduino controller.
This, along with J11 and J12 on the opposite edge of the board, allow it's
use as a "Shield" or expansion board for the Arduino. More on that below.
 |
|
The next picture, below, is the back 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.
| Function |
PC Parallel Port pin |
| X /EN |
14 nAutoFeed (out) |
| Y /EN |
17 nSelectIn (out) |
Z /EN
A /EN |
15 nInit (out) |
|
|
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 pink 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.
If you are going to install the relay driver, you need to do that before
you install the header for the cable that connects to each axis driver due
to a couple of slight screw ups with the reverse emf protection diode D8:
 |
| |
First, the header plastic for JP3 comes right to the edge of D8's pad
and so it will melt if you solder the diode in after the header.
CRITICAL: On version 4 boards, the marking of pin 1 on the reverse protection
diode, D8, for the relay driver is backwards. This has been corrected on
version 5. Pin one is actually toward the center of the board, not toward
the edge of the board as shown on the version 4 board. Installing this diode
as marked will result in a short when the relay driver is engaged. To correctly
install the diode, on either version, place the stripe on the diode case
/away/ from the edge of the PCB (away from the drive transistor, Q1) and
towards the center of the PCB. It's best to leave the leads long enough that
the diode is about 1/2 inch in the air..
The LED installs in the little circle just under the Y in RELAY on the top;
long lead in the square hole.
The other components are pretty easy, and can be installed on the bottom
or top; pin 1, long lead, postive lead in the square hole as always.
Leave the terminal blocks for last, and as always, try to work from the center
of the board out to the edge.
|
|
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
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.
Assembly is easy: Mount the diode, D6, first. The end with the band goes
in the square hole.
Ensure the power regulator, U2, is in as shown on the solder mask; with the
back to the outside of the PCB when inserted from the top. 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 capacitors with the longer lead in the hole closest
to the "+" outside the circle. The big 1000uF cap, C4, can be mounted either
on top or underneath. If you mount it on the bottom, and leave the leads
long, you can "lay it down" and secure it to the PCB with some double-back
tape or a bit of silicone. It's shown laid down on the top, just so you can
see the leads... mounting it like that could interfere with other components,
as you can see. If you want it on top, it's probably best to stand it up.
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.
Solder the terminal which replaces J4, 5 and 6 on last.
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.
NEW! The pulse kit has been extended to support a pushbutton switch
which will allow single stepping, bursts of steps or continuous stepping
depending on how long it is held. The kit has been updated to include a switch,
pull up resistor, and a wire to jumper the switch to an available PIC pin.
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 board. Bend on of the resistor leads
you saved in half and use it to connect pin 3 of J12 (at the "D" in the "A2D"
printed on the top of the board) to pin 4 (at the "D" in "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 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.
Note the end of the wire connected to the pad above R1 in the lower right
corner of this picture. On the back of the board, use the wire to jumper
RP2 pin 13 (marked as switch 1) over to R1 on the other side of the board.
That R1 pin is the one just before the "R". It is the round hole, not the
square one. Hold the board so that "R1" is right side up; the round hole
immediatly to the left of the "R". The other end of that wire goes into the
switch pin on RP2 near the other side of the board. Strip both ends, insert
and solder.
Install the ~1K ohm (BRN, BLK, RED) resistor between pin 1 and pin 5 of RP2
(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 S4 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 top. 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 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 availble, 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.
| Switch |
Parall Port |
Pin |
|
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. |
| S1 |
nAck |
10 |
|
| S2 |
Busy |
11 |
|
| S3 |
PError |
12 |
|
| S4 |
Select |
13 |
|
Eratta:
The marking of pin 1 on the reverse protection diode, D8, for the relay driver
is backwards. Pin one is actually toward the center of the board, not toward
the edge of the board as shown. Installing this diode as marked will result
in a short when the relay driver is engaged. To correctly install the diode,
place the stripe on the diode case /away/ from the edge of the PCB (away
from the drive transistor, Q1) and towards the center of the PCB.
Questions:
