8
Physical properties
E-blocks can be mounted onto a metal back-
plane to form a completely rugged system.
To facilitate this each E-block is fitted with 4
off 3mm holes spaced at multiples of 20mm.
M3 bolts can be used to mount the E-blocks
onto a backplane which has 4mm holes on a
regular 20mm grid. The spatial relationship
between the mounting holes on the
backplane, the holes on the E-blocks and the
spacing of each D-type plug and socket on
the E-blocks are such that each E-block will
fit into another, and yet still be mountable on
the backplane.
Mounting options for backplanes
There are several options for mounting
E-blocks on a backplane depending on your
circumstances:
• Temporary mounting with pillars
Custom moulded circuit board pillars are
available which allow you to loosely mount
boards to the backplane. This is ideal if you
are working through a course and frequently
reconfiguring the E-blocks system to give
yourself experience of different systems. Note
that these pillars are very tight initially but
soon loosen up. This is shown in profile in
Figure 5.
If you are reconfiguring your E-blocks system
less frequently then we suggest that you
use M3 bolts on all your E-blocks and that
you use a metal backplane to mount them
on. The E-blocks can be mounted on the
backplane with M3 self locking nuts - these
will keep the bolts secured onto the circuit
board and will act as spacers to keep the
board clear of the backplane. (See Figure
6). When you want to move the system
around then one or two additional nuts
behind the backplane will ensure your
E-blocks stay in place. For best results with
this mounting technique you should attach
the bolts and self locking nuts and then
slacken off the nuts by a quarter turn - this
allows the bolts a little movement in the PCB
mounting holes and makes them easier to
take off the backplane. If you are concerned
about preserving the painted finish of your
backplane then you can substitute the steel
bolts with nylon ones. However we have
found the powder coating of the backplanes
is sufficiently strong not to warrant this.
Using E-blocks on the bench
You do not need a backplane to use E-blocks
- you can simply connect them together on
the bench. In each E-blocks package you will
find a four small rubber feet to facilitate this.
These will provide a degree of protection for
your E-blocks boards and will help prevent
shorts from tinned copper wire and other
metal objects on the bench. The disadvan-
tage of this is that your E-blocks system will
not be secure and that the connectors will
be under more stress as the system is moved
about.
Figure 5 - board with mounting pillars
Figure 6 - board with 12mm bolts
M3 fixing
holes
M3 fixing
holes
20mm
20mm
PCB
Backplane
12mm M3 bolts
M3, M4 mounting pillars
PCB
Backplane