Hi everyone,

I have used the DT800 on a remote site to log 15 channels (mv) for 2 separate periods of 1 month each.I used an external 12v battery and the logging frequency was every half an hour. No default parameters were changed for the DT800.

I had a problem with the second period when the DT800 logged for 2 days and then the batteries were flat. This is different as the first monthly log period I had no problems with the batteries dying out. I did connect a GSM modem to the RS-232 port (powered separate & externally).

However, the modem was not used for communication at all though it was connected to the serial port all the time. I used a Wavecom M1306 modem with no auto power mode ie the modem was fully powered from a separate battery all the time.

Any thoughts on why the DT800 batteries (ext 12V and internal main 12V battery)drained out completely flat and I logged data for only 2 days out of 1 month that the system was installed at the remote site? If a fully powered modem is connected to the DT800 does it mean that the DT800 will not go to sleep? Why did the DT800 not sleep in between the half hourly scan cycle? DT800 version 4.08.0001

Any helpful comments are really appreciated.

Good morning,

Where did you have the battery connected to?

On the end of the DT800 there is a three way connector. The middle connection is the ground. If you connect the positive to the left hand side then the dataTaker assumes you have a permanent external power supply and will not use sleep mode. It is exactly the same as the round jack where the power pack plugs into.

The connection on the right hand side is for connecting external batteries. When connected here the dataTaker assumes it is a battery and will use sleep mode whenever possible. It will also not keep the internal battery charged.

I suspect when the test ran for two months the connection was for an external battery and the second time when it lasted two days it was connected to the main power connector.

Cheers,
Roger

Hi,

The battery was connected to the top right 2 clamps ie bypassing the internal battery charging circuit to enable the ext battery to last for more than just a few days. However, as I mentioned the only difference in the setup was the fact that I left a GSM modem connected to the datataker.

Is it possible that this prevented the DT800 from going to sleep in the normal mode? Even assuming that I connected the external battery in the wrong connector (I didn't) and it drained the external battery in a few hours, the DT800 should have then switched to logging from the internal lead acid battery which automatically means that it works in the low power mode by default?

However, the DT800 has not been logging any data at allover the period of time which implies the internal battery drained as well and it didn't work in the low power mode as it was supposed to ie it was kept awake somehow]
Good morning,

Where did you have the battery connected to?

Hi Roger,

Thanks for your input.

The battery was connected as to bypass the internal recharging circuit i.e. using the two right connectors. and in any case the internal lead acid battery was flat as well which indicates the DT800 switched to the internal lead acid battery after the external one was drained but it didn't go into the low power mode as is default behavior?

Does this mean that by leaving the modem connected to the RS 232 port, the DT800 will never go to sleep if it is not logging? Also, I was using a digital counter channel (C7) but this doesn't affect the DT800 trying to sleep, does it?

Cheers
D.

Good morning,

The dataTaker will sleep with modems connected to the serial port.

What speed are the counts occurring? Counters C1 to C6 have 4 bit hardware and so the DT800 needs to wake every 16 counts to handle the roll over. Counters C7 & C8 have 12 bit hardware so only needs to wake every 4096 counts. This means it better to use C7 & C8 if using sleep mode.

How are you powering the modem? If you are drawing the power from the dataTaker then this will reduce the battery life. The other thing to consider is the condition of the batteries. Lead acid batteries can and do break down with age.

Cheers,
Roger