OM-USB-2404-UI User's Guide
Functional Details
15
Half-bridge and full-bridge mode connections are shown in Figure 12. The dotted lines in the figure represent
the portion of the circuit that is only connected in full-bridge mode.
Figure 12. Half-bridge and full-bridge mode connections
Thermocouple mode
In thermocouple mode, connect the positive end of the thermocouple to HI, and the negative end of the
thermocouple to LO. This mode uses the ±1.25 mV range of the ADC to return a voltage reading. Use shielded
cables and twisted pair wiring, and ground the shielded cables.
Each channel has a built-in thermistor for cold-junction compensation (CJC) calculations. For improved CJC
sensor accuracy, operate the OM-USB-2404-UI in a stable temperature environment, and avoid placing heat
sources near the device or its connectors. Open thermocouple detection is not supported. Refer to the
Specifications
chapter for more information about accuracy. Thermocouple mode connections are shown in
Figure 13. Thermocouple mode connections
Excitation protection
The OM-USB-2404-UI excitation circuit is protected from overcurrent and overvoltage fault conditions. The
circuit is automatically disabled in the event of a fault condition. Whenever possible, channels automatically
recover after the fault is removed.
