Setting An Offset Value; Using Mx+B - Fluke 8845A User Manual

8845A/8846A
Users Manual

Setting an Offset Value

The offset function provides a means of displaying the difference between a measured
value and a stored offset value. This type of measurement is referred to as a relative
measurement.
There are two methods of entering an offset value into the Meter. The first method is to
enter a specified number into the offset register either through the front-panel or over the
remote interface. Previously stored values are replaced with the new value. The offset
value is stored in volatile memory and is set to zero when power is applied to the Meter
or the Meter receives a reset through the remote interface.
The second method is to measure the desired reference value through the Meter's input
connections and press Z. The measured value is placed into the offset register and the
display immediately starts showing the difference between measurements and the stored
value.
The Zero key cannot be used to zero a DB or DBM measurement. Refer to
"Measuring AC Voltage" in Chapter 4 of this manual.
To enter an offset value through the front-panel:
1. Press J
2. Press the MATH soft key
3. Press the OFFSETsoft key.
4. Press ENTER to set the value in the offset register.

Using MX+B

The MX+B function provides a means of calculating a linear value using a measured
value (X) and two constants: M and B. The constant M represents a gain, while the
constant B represents an offset.
To make an mX+B calculation:
1. Press J.
2. Press the MATH soft key.
3. Press the mX+B soft key.
To enter the M value:
4. Press the mX soft key
5. Press ENTER to enter the M value.
6. Press Bto return to the MX+B menu.
3-12
To select the digit to adjust, press either <-- or -->.
With the desired digit selected, press the soft key labeled -- to decrement the digit
or ++ to increment the character. The right most character is the multiplier. This
character can be set to p, n, , m, k, M, or G.
To select the digit to adjust, press either <-- or -->.
With the desired digit selected, press the soft key labeled -- to decrement the digit
or ++ to increment the character.
Note