Fluke 45 - 4-6. Entering Calibration Mode

45
Service Manual
4-8
4-6. Entering Calibration Mode
Always begin the calibration procedure as follows:
1. Allow the Fluke 45 to stabilize in an environment with ambient temperature of 18 to
28ºC and relative humidity of less than 70%. Then turn the Fluke 45 on, and allow it
to warm up for at least 1 hour.
2. The Cal Enable button is located on the right side of the display and is recessed
beneath a calibration seal. Enable the calibration mode by pressing the Cal Enable
button for about three seconds (CAL appears in secondary display.) Use a small
screwdriver or equivalent blunt-tipped object. Avoid using sharper-tipped objects
(such as pencils).
When the calibration mode is enabled, the unit first beeps, then displays VDC CAL.
From this point the calibration menu can be scrolled to a specific function using the
U
and T editor buttons. To display the first prompt for the selected calibration function
press the
E button. In the calibration mode, most buttons are disabled; only the E,
U, and T edit buttons and the Cal Enable button remain active. These buttons are
described more fully as follows:
1. Cal Enable button: Enables the calibration mode when pressed for 3 seconds. Exits
the calibration mode when pressed momentarily.
2.
U T Editor buttons: Used to scroll to the desired calibration function in the
calibration menu or to edit the displayed calibration prompt.
• Once calibration mode has been entered, the calibration menu appears in the
following sequence:
VDC VAC mA DC mA AC A DC A AC Ω Q Hz
The menu does not wrap; going from Hz back to V DC can only be accomplished by
successively pressing the
U button.
• Once
E has been pressed to initiate calibration prompting, press either U or
T once initially to enter the editor mode. Then use these buttons to edit the
calibration prompt value.
The calibration prompt value can be edited by digit. Use
T to select the digit
to edit. Use
U to increment the selected digit. To select a lower digit value,
continue incrementing with
U; the meter wraps from 9 back to 0. Press E
when the edited value is correct.
3.
E button: Used to select a calibration function, calibrate (store constants derived
from input source into memory), or exit editor mode.
Each time the Fluke 45 prompts you for a reference source, apply the requested source to
the appropriate input and COM terminals, allow for both calibrator and meter settling
time, and press the
E button. When E is pressed, the numeric display field blanks
while the Fluke 45 performs the necessary calculations. (Do Not change the reference
source while the display is blank.) If the calibration step is successful, the Fluke 45
displays an intensified reading equal to the calibration prompt value before changing to
the next prompt.
Note
The meter emits a beep and displays ’Error’ if a calibration step fails.
Usually, this happens if the reference is not within an anticipated range (5
to 15%, depending on the step.) At this point, the intensified reading equals
the raw uncalibrated reading taken on the reference input. Refer to
Calibration Failures in Chapter 5 for more information.