Fluke TRACKERTM 90100 - Manual (Page 53)

Customization
Setting the Electrometer Gains and Offsets
5
5-7
WARNING
ELECTROMETER OFFSET (ADZ)
The procedure for setting the electrometer offsets for current and charge is the same. For every
electrometer channel, repeat this procedure once. Turn the instrument off and disconnect the interface
cable if it is connected.
Always turn the Model 35360A TRACKER Display's
power off prior to connecting or disconnecting the
interface cable. Failure to do so may result in an
electrical shock.
Turn on the instrument. Place the 35360A TRACKER Display in rate mode. Turn off the Front Panel
Gain Factor (FPGF) and the Air Density Correction Factor (ADCF).
1. Reset the instrument. Note the dose rate offset value for the channel under adjustment displayed
on the VFD. Also note the old ADZ value for the channel under adjustment on the Display
Calibration Items screen. Calculate a new ADZ value using the following equation:
ADZ
New
= ADZ
Old
+ (Dose Rate Offset) / (Current Gain × ICCF × DUCF)
2. Add the value calculated in Step 1 to the original ADZ. Enter this value into the Display Calibration
Items screen of the Customization software. Be sure to enter it in the correct column and row. For
example, if you are setting the charge offset for the Top chamber, enter the calculated value in the
first column and second row.
3. Repeat Steps 1 and 2 if the value displayed on the 35360A TRACKER Display is not zero.
ELECTROMETER GAINS
The procedure for setting the electrometer gains differs for current and charge. For every electrometer
channel, repeat the gain setting procedure for current and charge. Turn off the Front Panel Gain Factors
and the Air Density Correction Factor. This procedure requires a special cable. Consult the factory for
details.
Electrometer Current Gain (IG)
1. Apply 15 nanoamperes (900 nC/min) to the input of an electrometer channel.
2. Check the measurement on the 35360A TRACKER Display's Front Panel. Calculate the new
Current Gain factor using the equation below.
t Measuremen
DUCF x ICCF x 900
Gain Current Old = Gain Current New
where Measurement is the value on the 35360A TRACKER Display, and ICCF and DUCF are
defined on page 60 and page 59 respectively.
3. Enter the value calculated in Step 2 into the Display Calibration Items screen of the Customization
software. Be sure to enter it in the correct column and row. For example, if you are setting the
current gain for the Right chamber, enter the value calculated in Step 1 in the fourth column and
third row.
Electrometer Charge Gains (QG)
1. Reset the instrument and apply 950 nanocoulombs to the input of an electrometer channel.
2. Check the measurement on the 35360A TRACKER Display's Front Panel. Calculate the new
Charge Gain factor using the equation below.
t Measuremen
DUCF x ICCF x 950
Gain Charge Old = Gain Charge New