Pathway DMX Pathfinder CR Manual - Manual (Page 33)

DMX Distribution System Page 33
DMXPathfinder - Hardware
repeat a hardware reset from the pushbutton to the Input Modules and the
other frames respectively. JP1 is a test jig port for factory use only.
PC COM Section (Sheet 1) -- UART U26 is used for controlling the PC COM
ports. Three physical ports are provided, one on the front panel of the
Master Module (J4) for a local portable PC using RS232C, and two on the
master frame backplane via J1 for a remote hardwired PC using RS232C or
RS422/485. Receiver U9 and transmitter U11 interface the remote PC to the
Master Module via RS422/485, while RS232 adapter U25 interfaces the local
and remote PCs via RS232C. Up to three PCs can be connected at the
same time.
Bus Buffer and Monitor Section (Sheet 2) -- DMX data present on the
Master/Input Frame Bus connects to the Master Module at J1. From here,
data moving in the send direction is buffered by U13 and U17, then placed
on the system I/O bus at J2. The Master Module is the only unit "talking"
onto the bus. Data moving in the return direction on the system I/O bus
appears at J2, is buffered by U15 and U19, and is passed back to the Input
Modules by J1. Multiplexers U12, U14, U16 and U18 monitor for the
presence of data on the send and return busses and pass this status
information back to the microprocessor via U20 and the processor data bus.
Display Section (Sheet 3) -- U1-U4 are demultiplexer/LED drivers for the
system I/O bus status LEDs. LED driver U5 is for the module status LEDs.
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 by the watchdog timer.
Power Supply Section (Sheet 3) -- AC power at 120 volts 60 Hz is brought
to the module by backplane connector J3. A polyswitch (self-resetting) fuse
protects on-board components. JP5 is a power input selection jumper (E1-
E2 and E3-E4 are jumpered for 120 volt operation, E2-E3 are jumpered for
240 volts). A power transformer T1 with two 8 volt secondary windings is
provided. T1's secondaries are paralleled for higher current rating, then
rectified by D3 and D4, filtered by C10/C11 and regulated at 5 volts by VR1.
The resulting VCC supply is used by all components on the board and is also
connected to the backplane via J1 to be used for active terminators on the
Frame Bus.