Thus, to calibrate an AA41-based Channel No. “x,” you need only turn ON the system
EEPROM SWITCH and then apply the following
FREQUENCY CALIBRATION (FRQ)
command:
FRQ x = i, u [CR]
For “i,” enter the manufacturer-supplied full-scale rating of the frequency source (or
the highest frequency expected to be measured), in
hertz. For “u,” enter the corre-
sponding value of the measured phenomenon, expressed in the desired engineering
units. You need not
zero the channel in this case. The FRQ command will only work if
Channel No. x has been assigned the proper “type” code (see Table 1).
Note that a channel calibrated by the FRQ command will report measurement data to
a precision matching that of the entered “u” value. If, for example, you're measuring
“liters per minute,” and enter a “u” of “750,” then all subsequent channel readings will
be rounded to the nearest liter per minute. If the entry is “750.0,” then all readings will
be rounded to the nearest tenth of a liter per minute.
TWO-POINT (DEADWEIGHT) CALIBRATION
Using the standard ZERO (ZRO) and FORCE (FRC) commands, this conventional
“zero and span” method can be applied to an AA41 channel if the full-scale rating of
the frequency source is unknown, and if the channel’s received frequency input is an
analog of another parameter—such as Gallons Per Minute—which has one or more
independently and accurately known calibration values. The mainframe’s
EEPROM
Write Protect Switch
must be ON for the ZRO and FRC commands to be effective.
See Manual Section 1.G.5 for a general discussion of this calibration technique.
AA41-2/4.10 SETUP AND/OR OPERATING CONSIDERATIONS
AA41-2 / AA41-4 DUAL / QUAD FREQUENCY CARD
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