Yaskawa Remote Display Unit RDU for use with MicroTrac DSD LAN - Manual (Page 3)

INTRODUCTION
The Remote Display Unit (RDU)
provides the MicroTrac DSD system with
the ability to have remote displays with a
minimal amount of wiring. The RDU has a
two line display; the top line is a 16
character alphanumeric (dot matrix) LED
display, and the bottom line is a 5-1/2 digit
numeric only LED display with a +/- sign
and a floating decimal point. The required
interconnections are an RS-485
bidirectional serial data bus (for the
communications) and DC power, either
regulated +5VDC or unregulated +8VDC to
+12VDC.
A channel select switch and a
channel range terminal on the rear of the
unit are used to identify the RDU channel
number. A scanning keypad interface is
provided to accommodate a 4 x 5 local
matrix keypad. An input is provided which
will enable the scanning of the keypad; this
makes provision for a "Keyboard Enable"
switch. Provision is also made for inputs
from one or two push buttons.
The RDU acts as a dumb terminal
under control of a Remote Display
Controller LAN Node PCB (RDC). All data to
be displayed is received from the RDC,
except for diagnostic test and error
conditions as will be described later. All
keypad or push button data will be
transmitted directly to the RDC with no
local echo.
This document explains the
hardware and software operations of the
Remote Display Unit (RDU).
HARDWARE DESCRIPTION
CONFIGURATION
The RDU consists of three interconnected
printed circuit boards mounted inside a
metal case designed for mounting in a panel
cutout. Two securing brackets with
tightening screws are provided loose with
the RDU, to be attached to the sides of the
case after it is in place in the panel cutout.
The front of the case has a red lens to
protect the display LEDs. At the rear of the
case, two-section terminal board TB1,
ribbon cable connector J2 and channel
select rotary switch S1 are accessible for
wiring and setup.
3 RD 791-10
POWER REQUIREMENTS
The RDU may be powered by a
regulated +5VDC or an unregulated +8VDC
to +12VDC power supply. If a regulated
+5VDC supply is to be used, then the
+5VDC and COMMON conductors should
be connected to TB1 pins 8 and 9,
respectively. +5VDC and COMMON can be
wired from RDC terminals J5(1) and J5(6)
respectively. If an unregulated +8VDC to
+12VDC supply is to be used, then the +
VDC and COMMON conductors should be
connected to TB1 pins 7 and 9, respectively,
in order to use the on-board +5VDC
regulators. In order to select a properly
sized power supply, the current (I)
requirement of the RDU must be known.
The current requirement is the same
regardless of the choice of incoming power.
The I requirement is as follows:
I for regulated +5 VDC or unregulated
+8VDC to +12VDC = 1020 mA