Specifications

Comments • The wiring diagram used for this example is on page 28.
• Specifying the gage factor as 2.11E-6 returns the strain
measurements in microstrain.
• A gage factor must be specified and an unstrained reference must be
measured for each channel.
• The REAL,64 format is selected because the HP 9000 Series
200/300 computer stores readings in that format.
• REAL,64 data is transferred to the computer in the IEEE 488.2-1987
Definite Length Arbitrary Block format. Data in this format is
preceded by a header consisting of: # <non-zero digit> <block
length>. In this program, the header preceding the measurement
data is #516000. The 5 represents the number of digits indicating the
block length (16000), and 16000 is the block length (2,000 readings
* 8 bytes/reading).
• When HP BASIC is used, the program’s ENTER @Dmm USING…
statement is used to remove the Arbitrary Block header:
# - tells the computer not to terminate the
ENTER until all
ENTER statements have completed.
X - tells the computer to skip the first character of the Arbitrary
Block header (#).
K,K - stores the <non-zero digit> and <block length> portions
of the header in the Ndig$ and Count$ variables respectively.
• The ENTER @Dmm;Rdgs(*) statement enters the readings into the
computer. Since a Line Feed (LF) follows the last reading,
ENTER
@Dmm
removes the LF character from the multimeter output buffer.
If the LF character is not removed, error -410 "Query Interrupted"
occurs the next time data is sent to the buffer. This (third)
ENTER
statement is only required when using the REAL data formats.
38 Making Strain Gage Measurements Chapter 3
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