How do I make Long Recordings?

The information provided is for help with Commtest Instruments products:

• MMS data loggers

QUESTION

How do I make long recordings with my MMS data logger, given that the battery life is limited to around 13 hours and assuming I cannot have a charger plug-pack connected?

ANSWER

The T4, T6V4, GP4 and GP8 data loggers have a triggger mode called 'Timer Based Trigger', which can be used to take very long recordings by making the instrument power down between samples.

Note: This feature is only available in firmware (Proflash) versions 2.50 and later. The latest versions are available from the download area of our website.

See your Owner's Manual for details on how to Proflash your instrument with new firmware.

To set up the Timer Based Trigger on the Instrument

• From the recording screen press MENU>3 for the Trigger menu.
• Press [2] for Timer Based and enter the following settings:

  Log data every	1 minute (see table below)
  Record	1 sample
  Sample Period	1 second
  After Recording	Power Down

  When a new recording is started, these settings will cause the instrument to wake up every minute (or whatever), add one sample to the recording and go back to sleep. The Log data every: field should be set to control how long your recording will last (until the battery goes flat), according to the following table:

  Recording to Last	Optimum rate	Conservative rate
  1 Day	10 seconds	20 seconds
  3 days	30 seconds	1 minute
  1 week	1 minute	2 minutes
  1 month	6 minutes	10 minutes

The 'Optimum Rate' is the very fastest that samples can be taken and still hope that the battery will last the specified time. This assumes that your battery is in top condition (see below) and no extra load is being placed on it (e.g. back light, or power to 4-20 mA sensors).

The 'Conservative Rate' is an indication of the rate you should select if it is essential that the battery lasts the speified time, and any of the conditions above are not ideal.

To keep your Battery in Top Condition

• Do not leave the charger connected permanently to the instrument. The battery will develop 'memory effect' and less charge will be available. Similarly, the battery should be cycled deeply rather than given frequent top-up charges.
• If a battery does appear to have developed memory effect, use the Recondition battery option under the System menu. This will fully discharge then re-charge the battery. See the topic Managing Battery in the Utilities section of your Owner's Manual.

FAQ ID: 11647 Last Reviewed: 3/09/2001