© 2010 SST Sensing Ltd 5 www.sstsensing.com
DS0074 Rev 7
ELECTRICAL CONNECTIONS
Output pins 8, 9, 12 & 13 are all referenced to the supply GND (pin 7). Due to high current flow in the supply GND, when
monitoring the 0-10V
DC
output (pin 9) it is recommended that a separate GND wire for the measurement system is taken
from PIN 7. This removes errors due to voltage drops in the power supply connections.
Every SST oxygen sensor has two heater connections which should be connected to pins 1 & 2 of the O2I-Flex, the
heater coil has no polarity. However when connecting to a sensor where the sensor housing is one of the heater
connections, pin 1 of the O2I-Flex should be connected to the housing.
SYSYEM BLOCK DIAGRAM
PIN
Description
1
Sensor Heater GND (Yellow, H)
2
Sensor (Yellow, H)
3
Sensor Sense (Blue, S)
4
Sensor Common (Black, C)
5
Sensor Pump (Red, P)
6
24V
DC
± 10%
7
GND
8
4-20mA Output
9
0-10V
DC
Output
10
Calibrate
11
Cycle
12
RS232 Tx
13
RS232 Rx
6 7 8 9 10 11 12 13
1 2 3 4 5
O2I
-
Flex
Oxygen Interface
