Pathway DMX Pathfinder CR Manual - Manual (Page 35)

DMX Distribution System Page 35
DMXPathfinder - Hardware
connected to the backplane via J1 to be used for active terminators on the
Frame Bus.
.3 INPUT MODULE -- DMS-IPM
There are one to eight Input Modules in the DMXPathfinder Master/Input
Frame. Each module incorporates the following hardware subsections:
Processor and Display Section (Sheet 1) -- The processor section
comprises the microprocessor U10, BCD card address switches SW1-SW3
and multiplexer U4, Frame COM bus receiver and transmitter U22 and U23,
watchdog timer/reset controller U21, status monitor multiplexer U7 and relay
demultiplexer U6. Only one BCD address switch (SW1) is installed, as the
maximum range of card numbers is 1 to 8. The display section consists of
demultiplexer/LED drivers U1 and U2, and LED driver U5. An LED display
daughterboard is soldered into header J4. Note that all LED displays with
the exception of "RUN" are controlled by the microprocessor. The RUN LED
is driven from the watchdog timer.
Crosspoint Matrix Section (Sheet 2) -- Two 4 x 16 crosspoint matrix
devices are provided. U11 is the matrix device for data received and moving
in the transmit direction through the system, and U14 handles data in the
return direction. U11's four channels of input data are derived from the
card's data I/O section. U14's 16 channels of input data come directly off the
system return data bus at J1 via buffers U15/U16. U11's 16 channels of
output data go directly to the system send bus at J1 via gated buffers U17
thru U20, which in turn are controlled by demultiplexers U12 and U13.
Gating is required to prevent more than one Input Module from trying to
place data on the I/O bus at the same time. Multiplexer U8 is used to
monitor activity on the 4 send and 4 return channels for the purpose of front
panel LED indication.
Data I/O Section (Sheet 3) -- Four identical data I/O subsections are
provided on the module. The second subsection will be described (top left of
sheet). An RS485 transceiver U29 and optocouplers U28/U30 handle data
flow in both directions. Three DPDT impulse-latching isolation relays K4-K6
operate in parallel to selectively connect or disconnect the two data pairs and
common to the external wiring network. 250mA data link Pico fuses are