17
Chapter 3
Signal I/O Connections
Screw terminals
OM-WEB Series hardware has four banks of screw terminals. Signal locations are shown in Figure 2.
Figure 2. Screw terminal pinout
1
OM-WEB-TEMP only. These pins are labeled
RSVD
(reserved for future use) on the OM-WEB-TC.
Do not make connections to the terminals labeled
NC
. Use 16 AWG to 30 AWG wire for signal connections.
Tighten screw terminal connections
When making connections to the screw terminals, be sure to tighten the screw until it is tight. Simply touching
the top of the screw terminal is not sufficient to make a proper connection.
Sensor input
You can connect up to eight temperature sensors to the differential sensor inputs (
C0H
/
C0L
to
C7H
/
C7L
). Each
channel pair has a 24-bit A/D converter, and can monitor one sensor category.
The OM-WEB-TC and OM-WEB-TEMP support thermocouple types J, K, R, S, T, N, E, and B. You can
connect two different thermocouple types to a channel pair.
The OM-WEB-TEMP also supports the following temperature sensor types:
Resistance temperature detectors (RTDs) – 2, 3, or 4-wire measurement modes of 100 Ω platinum RTDs.
Thermistors – 2, 3, or 4-wire measurement modes.
Semiconductor temperature sensors – LM35, TMP35 or equivalent
Do not connect two different sensor categories to the same channel pair
Each channel pair can monitor one sensor category. To monitor a sensor from a different category, connect the
sensor to a different channel pair.
Sensor selection
The type of sensor you select will depend on your application needs. Review the temperature ranges and
accuracies of each sensor type to determine which is best suited for your application.
