Measuring; Getting The Best Measurement Performance; Dynamic Sample Time (Dst) - Ametek mocon Dansensor CheckMate3 User Manual

18 User Guide

Measuring

Getting the best measurement performance

There are a number of factors to take into consideration when measuring O
The following guidelines should help you to obtain the best possible measurement accuracy
and performance from the CheckMate 3 device.
The device uses either a Zirconia (Zr) based O
The electrochemical (EC) O
sensor with regards to response time and lifetime.
The CO
2
Both sensors are temperature- and pressure compensated in software. However temperature
compensation requires stabilizing internally for some time.
In spite of the above efforts there are still limitations to what can be physically achieved.
To get the most out of your device, we strongly recommend that you read these next pages to
familiarize yourself with the various conditions, which may have impact on the
measurements.

Dynamic Sample Time (DST)

NOTE! Only valid for devices with an electrochemical (EC) O
The DST function uses a variable measuring time to ensure that all measurements are as
accurate as possible. Especially when measuring on packages with very different oxygen
contents, it may be necessary to extend the measuring time to ensure that the measurement
is correct.
Via the Product menu you can choose a nominal measuring time and basically this is the
applied measuring time. If the device detects a large change in the oxygen concentration, it
will automatically extend the measuring time, considering the oxygen sensor's response time.
The extended measuring time can not exceed twice the nominal measurement time.
If the additional measuring time is not acceptable (e.g. due to lack of headspace), the use of
DST can be disabled. If DST is disabled, we recommend to extend the measuring time to
achieve the same accuracy.
DST is enabled by default but setting can be changed as follows:
Change device to Supervisor access level - see

Enter General setup from the Main menu.

Scroll down to find and highlight the DST item.

Press

Press

NOTE! Do not disable DST function on the device without consulting an authorised
Dansensor Service Point. Disabling DST has great influence on the measuring
accuracy!
P/N 300042-I
05/2019
sensor has some limitations compared to the Zirconia based
2
sensor (if installed) is of the Non Dispersive Infrared (NDIR) type.
key to change DST setting to required setting (Yes/No).
key twice to return to the measuring screen.
EN Dansensor
sensor or an electrochemical (EC) O
2
"Access level" on page 45
®
CheckMate 3
and CO gasses.
2
2
sensor.
2
sensor.
2
for details.