PIGMY Boards: Sold out 4-Apr-99

Updated 24-Jan-96

These instructions are for the Revision B RELAY8 Board.

The Relay board is not a difficult project to put together or test.

<<<<  PIGMY   >>>>  Mates with J2 Header of my Pigmy board. A Pigmy
board can drive 16 relays using two RELAY8 boards. Port B of the PIC
device is used for the first board, and port C for the second. If the
PIC device is only an 18 pin device, then only 1 relay board can be
used. You will find instructions later, for using one board only via
port C of 28 pin devices if port B isn't suitable because of
configuration conflicts.

Solder in the two ULN2003 chips, or sockets if you are using them.
Make sure that the pin 1 orientation is correct.

Solder a 34 pin male header into position J1. If you wish to cascade
to a second board, solder another header into J2. (Read end of this
article for Port C *ONLY* operation before soldering in any headers).

Radio Parts Group have PCB mount screw terminals at 5mm, and Rod
Irving have them at .2" or 5.08mm centres. I have allowed for both
types by making the holes rather large and using two sets of 12 way
terminals instead of 1 long strip of 24.

A set of 2 PCB mount screw terminals can be soldered into the VBB and
Ground position.

The nine LED's can be soldered in. The cathode, or flat edge of the
LED is next to the mating resistor.

The nine 560 Ohm resistors can be soldered in. These are mounted
sitting straight up at right angles to the board. One leg needs to be
bend over the body of each resistor in a "U" shape fashion before
soldering the resistors in.

Before soldering in your Relays, you can easily test this board. If
you have a set of two male header pins and a test link, the +5 Volt
jumper "L1" can be installed. This will supply 5 Volts from your PPEX
board to the ULN2003's and the LED's.
_______________________________________________________________

PPEX OPERATION..... Connect up your PPEX board to an MS-DOS computer
printer port, and connect the RELAY8 board from OUTPUT HEADER 1 of the
PPEX board to J1 of the RELAY8 board using a 34 wire flat ribbon cable
with IDC crimp connectors.

Copy the file "RELAY8.NET" to "SEQ.NET" and run the "PPEXSEQ.EXE"
program. This will switch the appropriate LED's off and on in the net
list order.
_______________________________________________________________

Pigmy (and PICEX) OPERATION.....

Connect the RELAY8 board from J1 of the Pigmy board to J1 of the
RELAY8 board using a 34 wire flat ribbon cable with IDC crimp
connectors.

Watch out for the pin 1 to pin 1 connection of this cable. It will
need a twist in it if the boards are to be laid out next to each
other.

If it is installed the wrong way, a short will be placed across the +5
Volt supply of Pigmy which may damage the circuit or Plug Pack if this
short remained connected for a long time. The PIC chip should be safe
from any damage as a short will exist across its VDD supply.

Read more on this in the file "PICEX.ASS".

On your PICEX circuit (not-Pigmy) board, connect a 10K resistor from
ground to pin 1 of J1 using a couple of clip leads then power up. This
will invoke the POWER-UP diagnostics of PICEX which will turn the LEDs
off and on at 1 second intervals.

The board can be further tested by connecting up your PICEX board to a
PC and running a terminal program. Read PICEX.ASS and PICEX.CMD for
full details on this simple operation.
_______________________________________________________________

A second board can be connected up and tested by using another 34 wire
flat ribbon cable IDC jumper that connects J2 of the first board to J1
of the second cascaded board. Just check pin 1 orientation of this
cable before powering up. This connection can easily be reversed.

If all tests out OK, remove the +5 Volt jumper link and connect your
VBB power to the ground and VBB pads. I have used the term VBB, as the
voltage can be any operating voltage in the range of +3 Volts to + 50
Volts. This voltage must be DC and filtered at this point.

If you are using +12 Volt relays, this VBB supply can be found on the
"+" leg of your diode bridge on the PPEX board.

The PICEX board has its own set of POWER-OUT connections that can be
used for this purpose.

Any transformer or plugpack used, must be able to supply enough
current for your relays.

Five of the 5 large holes at each relay position of the board are used
to install the Rod Irving 12 Volt type SPDT Catalogue S14114. This is
the most popular relay used in E.A. kits. No additional contact
jumpers are required.

Another set of holes have been provided for the cheapest heavy duty
relay I could find, which is the Dick Smith Cat P-8008. These are
$2.95 each or $25.10 for 10. The catalogue price is incorrect for
single quantities. A Dick Smith misprint!

These relays have one relay contact below the coil position, so I have
provided 8 sets of links that must be installed on the component side
of the board. These links need to be installed before the relays are.

Note that the link at the right hand side of the board near relay 8,
has a right angle bend in it.

The coil holes for all relays must be at .1", .2", or .3" centres.
These coil holes can be seen on the overlay as the darkened two holes
just above the LED's. The right hand hole is one coil connection. The
3 left holes are all connected together and are the other coil
connection.

A fourth hole, way out at .475" centres has been included for the Dick
Smith Cat P-8008 relay.

The Tandy SPDT Microminature 12 Volt PC relay. Cat. 275-241 will need
the "NO" Normal Open, and "NC" Normal Closed contacts jumpered.

The Tandy SPDT 12 Volt Reed Relay. Cat. 275-233 will need the common
contact jumpered.

This is just a quick outline of what can be done with different types
of relays. You will find that with the .1" matrix holes at every relay
position, it isn't hard to install most PCB mount miniature relays.
_______________________________________________________________

Common relay types fitted so far to the RELAY8 board are:
Check out the ASCII circuit and Overlay Page for this.
_______________________________________________________________

Constructive Criticism...

Yes, someone actually has given me feedback. It's the only way I can
improve my products beyond my own horizons.

I guess there is always a new version board. My Rev. B board is a
great improvement over the Rev. A, but a few minor problems have been
found.

The PCB mount screw terminal holes need to be reduced in size for the
VBB and Ground positions.

As far as the main 2 by 12 way PCB mount terminal positions are
concerned, it's a compromise. To match both 5.00mm and 5.08mm centres,
large holes are needed. In order to reduce the problem, I made these
connectors 2 groups of 12 instead of 1 group of 24 pins.

If you use 5.00mm connectors, they only just fit. If you use 5.08mm
connectors, they are very loose and require lots of solder, but they
both fit without any real drama. So I will leave this one well enough
alone.

The two 34 pin headers J1 and J2 are very close to each other. If two
relay boards are to be connected up, and you wish to fit 34 pin IDC
plastic shrouded connectors so that a key-way is used to avoid
incorrect cable connections, you may need to file some of the plastic
away in order to get these headers to fit into the board.

I normally use bare 34 pin headers so this problem doesn't occur
however any future design will allow for this additional clearance
between J1 and J2.

If you have any thoughts or ideas that may enhance any future RELAY8
boards, I would be very happy to look at them.
_______________________________________________________________

Port B... Port C...

The FED Basic code uses Port B of the PIC for LCD interfacing.
This means that Port C must be used for a relay board. There are
several ways of overcoming this problem. I have tried 3.

1) Make up a special cable. No soldering, but cable looks very odd and
   perhaps un-professional. You will need to strip back one end of
   your flat ribbon cable into 3 groups, then swap the position of two
   of these groups, then crimp into a 34 pin female IDC connector.

   From pin one of the cable, slice back the first group of 16 wires,
   then the next 16. You should have the two +5V wires left. Reverse
   the position of the two 16 wire groups and crimp the cable. This
   will swap the B and C ports. As only one board is used, the Port B
   signals go nowhere.

OR

2) Install the 34 pin male header at J2 on the Relay board for
   connection to your Pigmy board. This will isolate Port B from the
   board. On the solder side of the board, install 8 jumpers from Port
   C of J2 to Port B of J1.

OR

3) Install an 18 pin header into J1 starting from the pin 1 end. Place
   your 34 pin IDC header and flat ribbon cable so that the port C
   signals line up with the 8 by ULN2003 inputs. Cut the tracks to
   isolate the now new +5V positions (2 cuts) and join these two new
   +5V pins to the board +5V if you are using +5V as VBB power on the
   board. Place a ground jumper around this new +5V position so that
   ground continuity is kept.

   This is the quickest and simplest for a permanent Port C board.
   Only 2 track cuts and 2 jumpers.

Perhaps I have missed another obvious method. Any other ideas?

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