
INSTALLATION
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2-6
SIG-00-07-11 SEPTEMBER 2012 (REVISED OCTOBER 2019)
Version No.: B.2
WARNING
VIU INPUTS SHOULD NOT BE WIRED DIRECTLY TO VITAL
OUTPUTS OF ANOTHER ELECTRONIC SYSTEM WITHOUT
FIRST TESTING TO PROVE THAT THE VITALITY OF THE
OUTPUTS OF THE ELECTRONIC SYSTEM ARE NOT
COMPROMISED DUE TO THE ELECTRICAL CHARACTERISTICS
OF VIU INPUTS.
WHEN THE VIU UNIT’S VITAL INPUTS ARE USED TO MONITOR
LAMP ENERGY AND THE LAMP HAS AN OPEN FILAMENT, THE
VIU WILL CONTINUE TO REPORT THE LAMP AS ILLUMINATED
AS LONG AS THE SYSTEM CONTINUES TO APPLY ENERGY TO
THE LAMP.
2.1.5.1
Discrete Vital Input/Output Connections
Each discrete pair on the I/O connector has both a positive and a negative terminal connection.
This allows for wiring of a larger variety of discrete I/O than using a common negative. It also
prevents problems such as ‘sneak paths’ when adjacent inputs are wired. Polarity is marked on
the case adjacent to each connector.
2.1.5.2
Connector Wiring Procedure
The female connectors supplied with the VIU for the vital input connections will accept wire
sizes in the range of #28 AWG to #14 AWG. The connectors contain spring-loaded cage-clamps
for attachment of the wires. Each connector consists of a row of wire receptors and actuator
spring holes to open and close the cage clamps. Wire each connector as follows:
1. Remove the supplied connector from the mating receptacle on the top of the VIU.
2. Select a proper gauge wire for the application (range is #28 to #14 AWG).
3. Strip approximately 5/16 inch (8 mm) of insulation from the end of the wire.
4. Insert the blade of a small screwdriver into the actuator spring hole associated with the
wire hole. The screwdriver blade should be no more than 0.10 inches wide and 0.020
inches thick (2.5 mm x 0.5 mm).
5. Lever the wire cage clamp open by pressing straight down on the screwdriver... Visually
note that the contactor receptacle has opened up sufficiently to insert stripped wire. Fully
insert wire into receptacle, taking care not to insert wire jacket insulation into metal
contactors.
6. Remove screwdriver. Gently tug on the just-inserted wire to ensure the receptacle
properly retains the installed wire.
7. Repeat for each wire to be added to the connector.
2.1.6 Serial Interfaces
The VIU is equipped with two serial ports.