SmarTek Systems SAS-1 Relay Interface Configuration And Connection - Manual (Page 3)

SmarTek Systems (www.smarteksys.com) 3
SAS Relay Interface Configuration and Connection
Many traffic monitoring sites in place (or
planned) and traffic counters use the traditional
controller interface approach of vehicle presence
relay signals. The SAS Relay Interface is used
with the SmarTek Acoustic Sensor (SAS-1) to
provide physical vehicle presence relay signals
to a cabinet controller or traffic counter . The
SAS Relay Interface (SAS-RI) is available
in two form factors (Figure 1). The shelf
mount version and the Type 170 card
version of the SAS-RI connect to the SAS-
CT using a SmarTek Systems supplied cable (CAT 5E with an RJ-45 connector on both ends).
The function of the SAS-RI is to acquire the bit-serial relay message stream from the SAS-1 and
convert the bit-serial relay messages into physical relay signals. These signals are open collector
opto-isolated vehicle presence signals. To sense the state of the signals, pull-up resistors are
required. The signals are brought out on individual conductors for the shelf mount SAS-RI and
on a card edge connector for the Type 170 SAS-RI card. When using the SAS-RI to provide per
lane vehicle presence relay signals, the SAS-1 default operating mode must be the Single Relay
or Dual Loop Mode. For the Dual Loop Mode, the “Loop” spacing must also be set in the SAS-
1. Before installation and connection of the SAS-RI, each SAS-RI must be configured using
push-pin jumpers on the SAS-RI circuit board. Configuration of the SAS-RI is required to
match the specific deployment of a single SAS-1 or multiple SAS-1 units (sharing a home run
cable).
Configuration and Installation
The shelf mount version brings ten (10)
relay signals out via a multi-conductor
cable connected at the rear of the SAS-
RI shelf mount unit. This cable is made
up of ten (10) conductors (open
collector) for ten (10) relay signals and
one common emitter (CE) as shown in
Figure 2. The two “CE” pins (Common
Emitter) are common to all the relay
signals. Power for the SAS-RI can
range from 8 to 24 VDC since the SAS-
RI has it’s own DC to DC switching regulator.
The SAS-RI has ten (10) LEDs (for detection indication), ten (10) channels of opto-coupled
relays, a reset switch, and two RJ-45 receptacles. The ten LEDs are organized with two per
channel (1A, 1B, 2A, 2B, etc.). The Reset switch resets the SAS-RI and after 6 seconds sends a
reset command to the SAS-1 if no bit serial relay message activity is detected.
Figure 1 SAS Relay Interface
Type 170 Card
Shelf Mount
Figure 2 SAS-RI Rear Panel Connector
Relays and Power Connector
Activity
LED
CE - Common Emitter Pwr - 8 to 24 VDC
1A
1B
2A
2B
3A 4A 5A
4B 3B 5B
CE
CE
Gnd
Pwr