User`s manual
XP8500 and Exp-A/D1294 s Connecting and Mounting Multiple Boards
Connecting Multiple Boards
Eight or more expansion boards can be connected (daisy chained) at one
time. The actual number of expansion boards may be limited by capacita-
tive loading on the PLCBus.
Be sure that each expansion board has a unique address to prevent commu-
nication problems between the controller and the expansion board.
Follow these steps to install several expansion boards on a single PLCBus.
1. Place all expansion boards right side up.
2. Use the ribbon cable supplied with the boards.
3. Connect one board to the main controller.
4. Connect another expansion board to the first expansion board,
connecting each boards header P1 to the adjacent boards header P2.
Figure C-1 illustrates a controller with expansion boards attached.
When several expansion boards are connected, there may be a voltage
drop along the network of expansion boards. No action is necessary as
long as the digital voltage, VCC, is greater than 4.9 V on the last board.
Do not twist the ribbon cable or mount the expansion
boards upside down! Damage may occur. Be sure Pin 1 of
P1 and P2 of each board matches up with Pin 1 of the
previous board. Pin 1 should be at the lower right when the
expansion board is right side up, that is, the board markings
are right side up.
H2
C11
J3
P1
EPROM
RAM
PIO
Z180
XP8500
XP8400 Controller
Relay 0
Relay 2
Relay 4
Relay 5
Relay 7
Relay 1
Relay 3
Relay 6
P2
P1 P2
Figure C-1. Connecting Multiple Expansion Boards
VCC can be measured at pin 2 on header P1, and GND is
pin 1 on header P1.
!