Measurement Computing USB-2001-TC - Manual (Page 12)

12
Chapter 4
Specifications
All specifications are subject to change without notice.
Typical for 25 °C unless otherwise specified.
Caution! Electromagnetic interference can adversely affect the measurement accuracy of this product. The
input terminals of this device are not protected for electromagnetic interference. As a result, this
device may experience reduced measurement accuracy or other temporary performance
degradation when connected cables are routed in an environment with radiated or conducted radio
frequency electromagnetic interference. To limit radiated emissions and to ensure that this device
functions within specifications in its operational electromagnetic environment, take precautions
when designing, selecting, and installing measurement probes and cables.
Analog input
Table 1. Input characteristics
Parameter Conditions Specification
Number of channels One
ADC resolution 20 bits
Input ranges ±73.125 mV, calibrated
±146.25 mV, not calibrated. Used for open
thermocouple detection.
Common-mode range Channel-to-USB ground ±30 V
Common-mode rejection ratio
(0 to 60 Hz) Channel-to-USB ground >145 dB
Noise rejection 50/60 Hz >80 dB
Temperature measurement
ranges Works over temperature ranges defined by NIST (J,
K, R, S, T, N, E, and B thermocouple types.) The E
type has a maximum limit of 900 ºC.
Conversion time 250 ms
Input bandwidth –3 dB 1 Hz
Differential input impedance 20 MΩ between isolated 3.3 V and ground
Input noise 2 µVpp
Open thermocouple bias voltage 3.3 V
Cold-junction compensation
sensor accuracy 0 to 65 ºC 1.25 °C maximum, 0.6 °C typical
Cold-junction compensation
sensor resolution 0.0625 °C typical
Overvoltage protection 30 V max between TC+ and TC–
Channel configurations
Table 2. Channel configuration specifications
Sensor category Conditions Specification
Thermocouple (Note 2) J, K, S, R, B, E, T, or N One differential channel
Note 1: Channel configuration information is stored in internal FLASH Program Memory on the
microcontroller by the firmware whenever any item is modified. Modification is performed by
commands issued over USB from an external application, and the configuration is non-volatile.
Note 2: The factory default configuration is undefined ‘#’.