Справочник Пользователя для National Instruments 9211

Thermocouple wire can be a significant source of thermal gradients if it 
conducts heat or cold directly to terminal junctions. To minimize these 
errors, follow these guidelines:

•

Use small-gauge thermocouple wire. Smaller wire transfers less heat 
to or from the measuring junction.

•

Run thermocouple wiring together near the screw-terminal connector 
to keep the wires at the same temperature.

•

Avoid running thermocouple wires near hot or cold objects.

•

If you connect any extension wires to thermocouple wires, use wires 
made of the same conductive material.

The following specifications are typical at 25 °C, unless otherwise noted. 
All voltages are relative to COM unless otherwise noted.

Number of channels................................4 thermocouple channels, 

1 internal autozero channel, 
1 internal cold-junction 
compensation channel

ADC resolution.......................................24 bits

Type of ADC ..........................................Delta-sigma

Input range

..............................................±80 mV, (not software selectable)

Common-mode range

Channel-to-COM

.............................±1.5 V

Common-to-earth ground

................±250 V

Common-mode rejection ratio (0 to 60 Hz)

Channel-to-common ........................95 dB

Common-to-earth ground

................>170 dB

Temperature measurement ranges ..........Works over temperature 

ranges defined by NIST
(J, K, R, S, T, N, E, and 
B thermocouple types)