0
Owner's of the Agilent Technologies Computer Hardware U2802A gave it a score of 0 out of 5. Here's how the scores stacked up:
2Features and Functions
34 Agilent U2802A 31-Channel Thermocouple Input User’s Guide
For bypass mode channels that are connected to valid voltage sources, the
10 MΩ pull- up resistor will cause additional current to flow through the
voltage source. However, this additional current measurement is small and
negligible for low impedance voltage sources.
For thermocouple mode channels connected to valid thermocouples, the
presence of the pull- up resistor introduces approximately 0.75 µA of
current through the thermocouple wires. This current introduces
additional errors when using thermocouples with high resistances, and the
measurement accuracy could be affected.
Cold junction sensor
A thermistor (RT1) is placed in between the screw terminals to measure
the temperature of the thermocouple junction for CJC. The output voltage
from the sensor is fed through a 4 Hz RC low-pass filter and buffered to
the AI148 pin on Rear Connector 1. The conversion from voltage to
temperature is done automatically by the AMM software.
Digital control
The digital control circuit consists of registers that controls the mode of
each channel and the open- thermocouple detect feature. The registers are
addressed and clocked via the digital I/O pins on Rear Connector 2. This
will be handled automatically by the AMM software.
EEPROM
The gain and offset calibration factors for each channel are stored in the
EEPROM during factory calibration and will be retrieved prior to taking
measurements. The EEPROM is tied to the digital I/O pins on Rear
Connector 2. The communication between the EEPROM and host PC is
automatically handled by the AMM software. In addition to the calibration
factors, the EEPROM stores the module ID, serial number, date of
calibration, which can also be retrieved before measurements are taken.
U2802A_UG.book Page 34 Tuesday, January 8, 2008 10:24 AM
Find Your Products By Category
Please Login
