National Instruments NI 9219 Thermocouple Mode

© National Instruments Corp. 17 NI 9219 Operating Instructions

Figure 10. Connections in Half-Bridge and Full-Bridge Modes

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 ±125 mV range of the ADC to return a

voltage reading. Use shielded cables and twisted pair wiring and

ground the shielded cable s. Each channel has a built-in thermistor

for cold-junction compensation (CJC) calculations. For improved

CJC sensor accuracy, operate the NI 9219 in a stable temperature

1 The dotted line represents the portion of the circuit that is connected

only in Full-Bridge mode.

HI

LO

EX+

EX– NI 9219

R

1

R

2

R

3

R

4

ADC

Wire

Wire

1

Contents

Main Safety Guidelines Safety Guidelines for Hazardous Voltages Safety Guidelines for Hazardous Locations Special Conditions for Marine Applications Wiring the NI 9219 Page Page Connecting Wires to the NI 9219 Connectors Wiring TEDS Channels Grounding and Shielding Considerations Figure 3. Connecting a Grounded Signal Source to the NI 9219 Figure 4. Connecting a Floating Signal Source to the NI 9219 NI 9219 Timing Options NI 9219 Circuitry Figure 5. Input Circuitry for One Channel Voltage and Current Modes Figure 6. Connections in Voltage, Current, and Digital In Modes + 4-Wire Resistance and 4-Wire RTD Modes 3-Wire RTD Mode 2-Wire Resistance and Quarter-Bridge Modes Half-Bridge and Full-Bridge Modes Thermocouple Mode Digital In Mode Open Contact Mode Sleep Mode Binary Data Excitation Protection Specifications Input Characteristics Page Page Page Page Input noise in ppm of Range Page Page Power Requirements Physical Characteristics Safety Safety Voltages Safety Standards Hazardous Locations Environmental Shock and Vibration Electromagnetic Compatibility CE Compliance Waste Electrical and Electronic Equipment (WEEE) Calibration Where to Go for Support