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5110 Relay Logic Modules

5110 Relay Logic Modules

  • Plug-in module with four internal dry
    contact relays
  • Coin-gold contacts to permit use in low
    current circuits and harsh
    environments without contamination
  • Installer programmable to perform
    required complex logic functions
  • Latching/non-latching operation and
    reset condition individually
    programmable for each relay
  • DPDT contacts 2A @ 30 VDC, 1A @ 120
    VAC (UL rating)
  • Drive capability for external relays


The SST Model 5110 Relay Logic Module
can be used when dry relay contacts are
required to perform various logic functions.
The dry contacts may be used to communicate
with and/or drive external equipment,
such as annunciators, SCADA data acquisition
systems, or host computers. The contacts
can also be used to perform various logic
functions within the NOVA-5000 Detection
& Control System.

Each Relay Module is equipped with four
two-pole relays. Three of the relays can be
used for external signalling, i.e. their contacts
are accessible through terminals on the
backplane and may be individually programmed
to be either normally open (NO) or
normally closed (NC) via ‘suitcase jumpers’.
The fourth relay is programmable for internal

Gold-plated labeled pin headers on the
printed circuit board provide access to each
of the eight backplane bus signals, the four
external inputs (connected to terminals on the
backplane), the relay control inputs (i.e.
latching, non-latching or reset input) and the
relay contacts. The module is prewired to the
most common configuration. Patch cords
with gold-plated connectors matching the pin
headers are available for connecting other
logic configurations. The backplane bus
signals and the external inputs are diode
isolated and can be freely connected to
achieve “or” gate logic combinations.
Various “OR’, “AND” and more complex
gate logic functions can be achieved by freely
combining relay contacts and inputs with the
patch cords. Additionally, any combination of
signals may be fed back into the NOVA-5000
backplane. Both fault and isolate loops may be
controlled by the relay contacts, if necessary.

The relay contacts are formed from coin
quality gold material, so that they are suitable
for even the smallest “microamp” current. The
gold also prevents any tarnishing of the
contacts in corrosive environments.

Six Light Emitting Diode (LED) indicators
are provided on the front of the module.
During normal operation, the green Power
LED will be the only visible indication on the
module. This indicates that 24 volt DC power
is being supplied to the module from the
redundant system power supplies. Just below
this green LED is a companion yellow LED
which is normally invisible. Should either of
the system power supplies fail, the yellow LED
will be visible to indicate a power fault to this
module. One green LED is provided for each
of the relays as a status display. When any
relay is activated the associated LED will be
lit. Pressing the Reset switch on the front panel
unconditionally causes all four relays to reset.

Each Model 5110 Relay Logic Module
mounts in one plug-in space in the NOVA-
5000 System Rack Assembly. Although not
required for normal programming or operation
of the module, a Module Test Extender Card
can be helpful to troubleshoot logic problems
during system design and start-up.

Architect’s and Engineer’s Specifications

System logic and external relay interface
capability shall be provided where required in the
system design by plug-in relay modules. Each
module shall include four (4) relays with dry contact
outputs which can be set to either normally open
(NO) or normally closed (NC). Relay contact
material shall be gold, platinum, or palladium
suitable for use in dry circuits in corrosive atmospheres.
The system designer shall be able to custom
program these inputs in various combinations of
“AND” and “OR” gates to activate the desired
outputs. All module connections shall be via
dedicated screw terminals on the associated module
backplane. The Module shall obtain operating power
from either of the dual redundant system power
supplies. Failure of either supply shall be indicated
on the module front panel, and shall generate a
“System Fault” pulse signal. Safety Systems
Technology Model 5110 Relay Logic Modules, or
approved equivalent, shall be supplied.

Technical Specifications and Ordering Information

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Logic Inputs: 4 external, 8 internal provided, 24 VDC nominal
Pulled up to +24 VDC. Connect to 24 VDC common to
activate, or drive from other NOVA-5000 modules.
Relay Outputs: 3 external, 1 internal provided, double pole, 2.0
amp @ 30 VDC, 1.0 amp @ 125 VAC resistive
Front Panel Indicators: Power On, Power Fault, Relay A, B, C, D activation
All indicators are light emitting diodes (LED’s)
Internal Adjustments: Logic Matrix with user installed plug-on jumpers
Set to perform required system logic functions by installer. May
be changed at any time.
Power Requirement: 24 VDC, 80 mA standby, 40 mA alarm per relay
Size: 0.99 inch wide, 5.06 inches high, 7.4 inches deep
Requires 1 mounting space in SST standard mounting rack.
Weight: 7 ounces


35110 Model 5110 Relay Logic Module
45110-3 Optional package of 10 jumper wires for programming
35360 Optional Module Test Extender Card