Hi,
in our company, we use CR1000 in combination with NL115.
We store 10-minute data and 1-second data in two tables on a CF card.
Is there a danger of writing errors if the power supply of the CR1000 is interrupted while storing data?
If yes - do you recommend to use an UPS to avoid this?
The battery that's powering the CR1000 basically is its UPS. I hope you're not just running the CR1000 with a 12 volt transformer and no battery.
Thanks for your fast reply.
But what happens if the battery is empty or broken?
Here is a suggestion, how to prevent this problem:
Is there a device (perhaps an internal puffer battery or capacitor) inside the logger, which has enough energy to power the writing process? If the logger recognizes that the 12V supply is down, the puffered energy is used to finish the actual writing process and the program is automatically stopped.
Do you think this could be realized in a future OS?
What you ask for already happens as:
The datalogger stops running its program when its battery voltage drops below about 9.6V. Because of this, generally, no new data will be written to the card below 9.6 V.
The logger and its memory cards will continue to run down to much lower voltages than 9.6 V (down to around 6-7 V).
If the logger is powered off an external battery supply this should avoid all problems of the logger trying to write data to the card when the power is failing, as it should take some while (many minutes if not hours) for the voltage to drop from 9.6 to 7 V by which time any residual writes to the card to have finished.
However, if you have a dubious supply that can fall rapidly there will still be risk of a card corruption. Adding some extra mechanism you ask for is unlikely to help in that circumstance as most flash cards have their own microcontrollers that run on, tidying up and managing the flash "disk", after the logger writes new data. So there is no guarantee of anything in that event.
OK. If I understood correctly, the only thing I have to do is to put a battery device (e.g. Campbell PS100E-LA) between the 230VAC/24VDC transformer and the CR1000, right?
Yes, except
a) the PS100 will not operate well (it will get hot) if charged from 24 V DC as it is designed to work with an 18 V supply.
b) without it the logger will not work well if running from 24 V DC as you say you have - it might even be damaged, or at least get very hot. It maximum supply voltage is 16 V DC.
a)
The manual from the PS100 states an input voltage of 15...28VDC or 18VAC.
So, my assumption was, that 24VDC are OK.
b)
We operated the logger with a 230VAC/12VDC transformer.
So, the 16VDC were not exceeded.
With respect to the absolute DC limit of the PS100 you are right, but we do not supply 24 V DC supplies ourselves because the charger on the PS100 can get hot if either a lot of current is drawn in recharging the battery or providing power to the load. We normally supply 18 V AC or DC supplies.