1. Put the instrument into standby (by pressing the POWER key).
2. Then hold down the STO button while switching the instrument back ON. The LCD displays the
message Sto for about one second.
3. Normal gas concentration measurements are displayed for about two minutes.
4. After two minutes the instrument displays the sample number (starting at 000), then the gas
concentration measurement value followed by [- - -] to indicate the measurement is being stored.
5. This storage sequence repeats automatically, at the rate specified by the Hach 3654 program
Sampling Rate menu. Values are stored sequentially in sample numbers 000 through 499.
Note: If you have not cleared previously stored values, the storage sequence automatically overwrites the older
values, as they are stored.
6. To end automatic storage, put the instrument into standby (by pressing the POWER key) while it
is in normal measurement mode and not while it is in the process of automatically storing data.
7. Switching ON again without holding down the STO button returns the instrument to measurement
mode.
Note: If you accidentally interrupt the automatic data storage by switching off the instrument while it is in the
process of storing a value, and you then attempt to download the stored values by the Hach 3654 program, you
will get a Windows Checksum Error message, and you will not be able to view the measurement data. If this
happens, go back to the instrument and manually log one more value. Refer to
on page 15. You can then download your original set of values to your PC.
Manual data acquisition
Note: You cannot store measurement data manually if the instrument has already been set up to store the data
automatically.
1. For the first measurement you wish to store, press the STO button once to display a sample
number. The default sample number is 000 (for first time access), or the last used memory
position where data was stored, incremented by a value of 1.
2. You can increase or decrease this number by pressing the Up/Down Arrow buttons within three
seconds.
3. Should you decide at this point, not to store this particular measurement, just wait five seconds
and the display returns to measurement mode. You may also exit this routine by pressing the
MEAS button.
4. Press STO a second time, within five seconds of the first. The instrument then displays a brief
clearing [- - -] message, followed by the gas concentration measurement value for about three
seconds.
5. The [- - -] message is displayed as this measurement value is stored.
6. Repeat the above steps to store additional measurements.
If you stored the first value as sample 001, the instrument automatically increases the next
storage location, and labels it sample 002. You can increase or decrease this number by pressing
the Up/Down Arrow buttons. If you label a sample number the same as a previously stored
measurement value, the new measurement value overwrites the previously stored value.
Viewing stored measurements
1. Put the instrument into standby (by pressing the POWER key).
2. Hold down the Up Arrow button while switching the instrument back ON. The LCD displays a
sample location number.
3. Scroll through the numbered sample locations of all the stored values using the Up Arrow and
Down Arrow buttons.
4. To view the actual gas concentration measurement value at a particular sample number, press
the STO button. The LCD now displays the stored value for that sample number.
Manual data acquisition
English 15