160
This is the A-head
Part II: More Hacking Techniques
When you are done, you should have quite a forest of lamp stands, as
shown in
Figure 8-11
.
5. Connect the relay drivers to the ISA I/O card
The second most time-consuming task will be wiring the digital output
board to the relay drivers. The key to getting things right is careful planning
and excess labeling of all wires and connectors.
You can see an overview of how all of the outputs from the ACL-7122 ISA
card will be connected to the relay drivers in
Figure 8-12
. Each 50-pin
connector on the 7122 board controls three relay driver boards. A 50-pin
ribbon cable is required for each connector and group of three relay driver
boards. Build six circuit boards according to the schematic in
Exhibit D
.
Each of these boards will connect the PC digital I/O card to three sets of
relay drivers.
The most foolproof way to make the connection between the output board
in the PC and the relay drivers is by building two connector interface cables
per 50-pin connector on the ISA card. This cable pair makes the connec-
tions more durable by taking stress off of the delicate ribbon cable from the
ISA card, and allows for easy troubleshooting in case something does not
work immediately.
ACL-7211 connector #1
BGHL relay
driver
BGHL relay
driver
BGHL relay
driver
ACL-7211 connector #3
BGHL relay
driver
BGHL relay
driver
BGHL relay
driver
ACL-7211 connector #5
BGHL relay
driver
BGHL relay
driver
BGHL relay
driver
ACL-7211 connector #2
BGHL relay
driver
BGHL relay
driver
BGHL relay
driver
ACL-7211 connector #4
BGHL relay
driver
BGHL relay
driver
BGHL relay
driver
ACL-7211 connector #6
BGHL relay
driver
BGHL relay
driver
BGHL relay
driver
To lamps and relays
Figure 8-12:
ISA card to relay driver overview
Figure 8-11: Forest of lamp stands