JF-1A Conductivity Sensor
A440-009
Page 35 of 56
FEBRUARY 2009
reporting low values (less than 5 pS/M) the user can be satisfied that the sensor
is clean. If the reading in air is less than +/- 2 pS/M skip onto section 3.5 “Set
Scale”, otherwise perform section 3.4 Reset Zero.
3.4 RESET INSTRUMENT ZERO READING
a) Note the value read with unit in air, as example JF-1A reading 4.3 pS/M, the
offset is high by 4.3 pS/M (label OFFold).
b) Place the unit in open mode by sending the “***O” command.
c) Read the current offset by sending the “ZERO” command (label as ZEROold).
d) Mathematically determine the new ZEROnew = ZEROold – OFFold.
e) Enter new calibration value using command “ZERO=ZERONEW”.
g) Check by returning to run mode using the ***R command.
h) Iterate steps a-g as is needed to gain a reading less than 2 pS/M.
i) Save constant by returning to Open Mode and using the “***E” command.
2.5 SCALE CHECK SENSOR
a) Using either the calibrated Hand Held Meter or the in calibration JF-1A sensor
measure the value of a beaker of fuel. Add fuel or additive to obtain a
value in the beaker of 1600 pS/M +/- 200 pS/M. Once established record
the value for use in this process, label that value as C-std.
b) Place the sensor in a fuel additive mixture; ensure that bubbles are not trap
in the electrode region by visual inspection.
c) Note the value read with unit in the sample, as example JF-1A reading 1575
pS/M, record this value as C-old.
d) Place the unit in open mode by sending the “***O” command.