Measurement Specialties USB-5201 - Manual (Page 22)

22
Chapter 5
Specifications
Typical for 25 °C unless otherwise specified.
Specifications in italic text are guaranteed by design.
Analog input section
Table 1. Generic analog input specifications
Parameter Conditions Specification
A/D converters Four dual 24-bit, Sigma-Delta type
Number of channels 8 differential
Input isolation 500 VDC minimum between field wiring and
USB interface
Channel configuration Thermocouple sensor type
Differential input voltage
range Thermocouple ±0.080 V
Absolute maximum input
voltage ±C0x through ±C7x relative to GND
(pins 9, 19, 28, 38) ±25 V power on, ±40 V power off.
Input impedance 5 Gigohm, min.
Input leakage current Open thermocouple detect enabled 105 nA max.
Normal mode rejection ratio f
IN
= 60 Hz 90 dB min.
Common mode rejection ratio f
IN
= 50 Hz/60 Hz 100 dB min.
Resolution 24 bits
No missing codes 24 bits
Input coupling DC
Warm-up time 30 minutes min.
Open thermocouple detect Automatically enabled when the channel pair is
configured for thermocouple sensors.
The maximum open detection time is
3 seconds.
CJC sensor accuracy 15 °C to 35 °C ±0.25 °C typ.,
±0.5 °C max.
0 °C to 70 °C -1.0 to +0.5 °C max
Channel configurations
Table 2. Channel configuration specifications
Sensor Category Conditions Specification
Thermocouple J, K, S, R, B, E, T, or N 8 differential channels
Note 1: Channel configuration information is stored in the EEPROM of the isolated 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 made non-volatile through the
use of the EEPROM.
Note 2: The factory default configuration is Type J.