Keysight 34972A User Manual

7Tutorial
288 Keysight 34970A/34972A User’s Guide
Calculation Error
An error is inherent in the way a thermocouple voltage is converted to a
temperature. These calculation errors are typically very small compared to the
errors of the thermocouple, wiring connections, and reference junction (see page
278).
DC Voltage Measurements
To make a useful DC meter, a “front-end” is required to condition the input before
the analog-to-digital conversion. Signal conditioning increases the input
resistance, amplifies small signals, and attenuates large signals to produce a
selection of measuring ranges.
Signal Conditioning for DC Measurements
Input signal conditioning for DC voltage measurements includes both
amplification and attenuation. A simplified input to the internal DMM is shown
below.
For input voltages less than 12 VDC, the Low V switch is closed and applies the
input signal directly to the input amplifier. For higher voltages, the High V switch
is closed and the signal is attenuated 100:1 before being applied to the input
amplifier. The input amplifier gain is set to one of three values (x1, x10, or x100) to
yield a signal in the range of ±12 VDC for the analog-to-digital converter.
HI
LO
Low V
High V
100:1
X1
X10
X100
Ranging
+/- 12 Vcd to
Analog-to-Digital
Converter

Keysight 34972A Specifications

General

Model	34972A
Category	Data Acquisition/Switch Unit
Manufacturer	Keysight Technologies
Scan Rate	Up to 250 channels/sec
Voltage Measurement Range	100 mV to 300 V
Resistance Measurement Range	100 Ω to 100 MΩ
Operating Temperature	0 °C to 55 °C
Storage Temperature	-40 °C to 70 °C
Switching Modules	Supports plug-in modules
Current Measurement Range	1 µA to 1 A
Temperature Measurement	Thermocouples, RTDs, and Thermistors
Interface	USB, LAN
Memory	50, 000 readings
Weight	3.6 kg