OM-WEB Series User's Guide
Introducing the OM-WEB Series
8
Supported sensor categories
Sensor category
OM-WEB-TC
OM-WEB-TEMP
Thermocouple (J, K, R, S, T, N, E, and B)
Resistance temperature detectors (RTDs)
(2, 3, or 4-wire)
Thermistors (2, 3, or 4-wire)
Semiconductor temperature sensors
(LM35, TMP35 or equivalent)
The sensor category is software-selectable for each channel pair. With the OM-WEB-TEMP, each channel pair
can connect to a different category of sensor. The sensor category between the channels that constitute a
channel pair cannot be mixed. However, thermocouple types within a channel pair can be mixed.
Four integrated cold junction compensation (CJC) sensors are provided for thermocouple measurements. Each
CJC sensor is dedicated to one of the four channel pairs. An open thermocouple detection feature lets you detect
a broken thermocouple. An on-board microprocessor automatically linearizes the measurement data according
to the sensor category. Built-in current excitation sources are provided for resistive sensor measurements (OM-
WEB-TEMP only)
Alarms
OM-WEB Series device feature eight independent temperature alarms. Each alarm controls an associated digital
I/O channel as an alarm output. The input to each alarm is one of the temperature input channels. The output of
each alarm is software-selectable as active high or low. User-configurable threshold conditions activate each
alarm. When an alarm is activated, the associated DIO channel is driven to the active output state selected.
Digital I/O channels
Eight digital I/O channels are provided to communicate with external devices and to generate alarms. The
digital bits are software-selectable for input or output. The digital output voltage is switch-selectable for 3.3 V
or 5 V logic. A screw terminal is provided for pull-up or pull-down configuration.
The digital I/O channels power up in input mode unless the bit is configured for an alarm. When a digital bit is
configured as an alarm, that bit is configured as an output and assumes the state defined by the alarm
configuration.
If you need to log data or display data graphically
OM-WEB Series devices display current data read from the device, and does not log or store historical data. For
logging or trending needs, use the TracerDAQ software included on the
Software for OMB-DAQ-2400,
OM-USB, OM-WEB, and OM-WLS Series Data Acquisition Modules
CD.
