H72.0.01.6C-02
Operating Manual GMH 3431
page 11 of 14
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The device has 2 channels:
- Channel 1: current measuring value Cond, rES, TDS oder SAL (base address)
- Channel 2: temperature value
Supported functions:
1 2 Code Name/Function
1 2 Code Name/Function
x x 0
Read measurement value
x x 200 Read min display range
x x 3
Read system state
x x 201 Read max display range
x 12
Read ID number
x x 202
Read display range - unit
x x 204 Read display range - decimal point
x 208 Read
#
of
channels
x x 176 Read min measuring range
x 222 Read power off time (Conf-P.oFF)
x x 177 Read max measuring range
x 223 Set power off time (Conf-P.oFF)
x x 178 Read measuring range unit
x 233 Read real time clock (CLOC)
x x 179 Read measuring range decimal point
x 234 Set real time clock (CLOC)
x x 180 Read kind of measuring of sensor
x 240 Reset
x x 199 Read kind of measuring of display
x 254 Program version
The measuring- and display range values read back from the interface are always in the
selected measurement unit!
9 Adjustment of temperature input
The temperature input can be adjusted with offset and scale. A reasonable adjustment presumes reliable
references (e.g. ice water, controlled precision water bath, etc.).
If the inputs are adjusted (i.e. offset and scale are different from default settings) the device will shortly
display “Corr” after turned on.
Default setting for offset and scale are ‘off’ = 0.0, i.e. inputs are not changed.
Zero point correction:
Displayed value = measured value – OFFS
Zero point and slope correction:
Displayed value = (measured value – OFFS) * (1 + SCAL / 100)
Displayed value °F = (meas. value °F - 32°F - OFFS)
•
(1 + SCAL / 100)
10 Automatic adjustment/calibration of cell correction
Besides the direct input of the cell correction (see below) via the menu (“CELL Corr”) the cell correction can
also be determined automatically:
Manual adjustment
or
Adjustment with reference solution
Menu selection:
“CAL Edit”
“CAL rEF.S”
Menu
selection
of
desired
solution
1413 µS/cm
0.01 M KCL
2.76 mS/cm
0.02 M KCL
12.88 mS/cm 0.1 M KCL
50 mS/cm
KCL
111.8 mS/cm 1 M KCL
Values for 25°C, the temperature
dependency of those solutions are known
by the device and are compensated
automatically.
Press Cal-key for 2 s,
start of calibration
“actual value” e.g. “1723 µS/cm”
“value of solution” e.g. “1413 µS/cm”
and CAL with rotary symbol and CAL with rotary symbol
Calibration
Select desired display value
wait until device measures stable value
with buttons “up” and “down”
and
confirm
with
“enter”
Afterwards the device returns to the normal measuring operation mode or - if so - displays an error message.
The resulting cell correction can be seen in the menu at “CELL Corr” and the calibration history.
