18
Chapter 5
Specifications
All specifications are subject to change without notice.
Typical for 25°C unless otherwise specified.
Specifications in
italic text
are guaranteed by design.
Analog input
Table 1. Generic analog input specifications
Parameter
Condition
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 GΩ, 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
Condition
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 or
wireless 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
.
