Page 9
Find us at
www.keysight.com
Keysight quality
We know you can’t afford instrument downtime due to hardware
failures and unscheduled maintenance. That’s why our engineers
designed reliability into the DAQ970A: A rugged enclosure,
state-of-the-art surface mount construction throughout, reduced
parts counts, and rigorous and thorough testing on all aspects of
the product.
Take the guesswork out of relay maintenance
The DAQ970A uses our proprietary relay maintenance system to
help you to predict relay end-of-life and avoid costly production
line downtime. It automatically counts every individual switch
closure and stores it in nonvolatile memory on each module. You
can query the total number of cycles on any individual channel
so you can schedule maintenance and avoid erratic end-of-life
failures.
Spec interpretation guide
The following pages list the technical specifications for the
Keysight DAQ970A Data Acquisition/System and its modules. The
explanations and examples below are helpful in understanding
how to interpret these specifications:
– Measurement accuracy is specified as percent of reading plus
percent of range, where reading is the actual measured value
and range is the name of the scale (1 V, 10 V, etc.)—not the
full scale value (1.2 V, 12 V, etc.).
– DMM measurement accuracies include all switching errors.
Switching errors are also listed separately in the module
specifications section. Temperature measurement accuracies
include ITS-90 conversion errors. The thermocouple
accuracies include the reference junction error as well.
– Accuracies are listed as either 24-hour, 90-day, or 1-year
specifications. This refers to the length of time since the
instrument’s last calibration. Use the specification that
matches your calibration cycle. The 24-hour specifications
are useful for determining short-term relative performance.
Example 1: Basic dcV accuracy
Calculate the accuracy of the following measurement:
9 V dc input
10 V dc range
1-year accuracy specifications
Normal operating temperature (18 - 28°C)
From the following page, the 1-year accuracy is:
0.003% of r 0.0004% or range
Which translates into:
(0.003/100 x 9 V)+ (0.0004/100 x 10 V) = 310 μV
For a total accuracy of:
310 μV/9 V = 0.0034%
Example 2: Extreme operating temperature
When the DAQ970A is used outside of its 18 - 28°C temperature
range, there are additional temperature drift errors to consider.
Assume the same conditions in Example 1, but at a 35°C operat-
ing temperature.
The basic accuracy is again:
0.003% of r 0.0004% of range = 310 μV
Now, multiply the 10 V temperature coefficient from the following
page by the number of degrees outside of operating range for
additional error (non ACAL):
(0.0005% r 0.0001% range)
/°C x (35 - 28°C) =
(0.0005% r 0.0001% range)
/°C x 7°C =
0.0035% r 0.0007% range = 385 µV
Total error is then:
310 μV + 385 μV = 695 μV or 0.0077%
www.allice.de
Allice Messtechnik GmbH
