Input Lines
The 4803DVR Board can be confi gured so that
all 40 lines are relay driver outputs or the fi rst 8 or
16 digital I/O lines can be connected directly to
the Interface board and used as standard TTL I/O
lines. Rocker switches and jumpers on the 4803DRV
Board bypass the relay drivers on bytes 1 and 2 and
connect the terminal strip signals directly to the
interface board.
The confi guration choices are:
TTL I/O
Relay Driver Outputs
0
40
8
32
16
24
The 4803DVR Board terminal strip connections
are identifi ed by bytes and bit, so they easily relate
to the signals on the companion Interface Board.
Standard bit commands like ROUTe:CLOSe or
ROUTe:OPEN can then be used to operate the relay
drivers. Output polarity is set high true for the relay
driver signals.
An External Reset input can be used to reset the
Interface board
Built-in Power Supply
The 4803DVR obtains power from the same power
supply that drives the external relays. The relay
power is used as the return for the drivers' internal
anti-backlash diodes and to power the companion
Interface Board. The user should still use relays with
built-in anti-backlash diodes to minimize RFI. The
4803DVR contains a small switching regulator that
converts 4 VA of relay power into 5 Vdc to power
the companion digital board,. This eliminates the
need for a separate 5 volt power supply.
4803DVR Board Assembly
Figure 2 shows how a 2003, 2303, 4803 or 8003
Interface Board with a circuit-side connector mounts
on the 4803DVR Board. The board is positioned over
J1 on the 4803DVR Board and pressed into place.
A pair of 0.688 high female-to-male standoffs holds
the front portion of the two boards together. The
rear portion is held by the mating force of the two
64 pin DIN connectors. Signal and power wires are
attached to the terminal blocks.
Standard Interface Boards with their digital
connectors on the component side can be used with
the 115522 version 4803DVR Board. The 115522
DVR Board has its digital connector mounted on
its circuit side (bottom) of the PC board so it sits on
the Interface Board as shown in Figure 3. A pair of
0.688 high standoffs holds the two boards together.
Standard 8003s with their vertical RJ-45 connector
cannot be used with the 115522 4803DVR
Board because the board blocks the RJ45
connector.
Digital signals identifi ed
by byte and by bit
R e l a y
p owe r
input
Switches connect terminals to board input lines
5 volt power supply
Mating connector for
the interface board.
Figure 3 115522 Relay Driver Board on top of a
standard Interface Board
115490 4803DVR Board
Relay
Power
Supply
+
-
V+
V Return
4803DVR Board
External Relay Connections
Output
Diode
Relay
Coil
+
-
Off
On
Byte 3, Bit 0
Byte 1, Bit 0
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Figure 1 Partial 4803DVR Board Schematic
Figure 2 115490 4803DVR Board and an Interface Board
with a circuit-side DIN connector.
1.237
Screw Terminals
Interface Board with Digital Connector on the circuit-side
4803DVR Board
Standard Interface Board with component side connector
1.825
Screw Terminals
4803 GPIB Headers
4803DVR Board
4803DVR: Description