Hi,

I am using the +5V output to power a humidity sensor, I have used the command +5VSW=1 and set the logger up so that the 12V subsystem is continuously powered. However when I run the logger, the +5V works for short scan times (5secs) but for 15min scans the +5V does not switch on and so the sensor gives a bad reading.

Does whether having the USB connected affect whether the +5V SW is available, because it seems to work if the USB is left connected to a laptop.

Hi Hillzider,

Internal 5V output should be available continuously when you have PWR5V=1 and P21=1 setting.
USB power uses different path than 5V power and they are not directly interlinked.

Notes:
It is not +5VSW=1 but PWR5V=1

Best regards,
Rudy Gunawan

Hi Rudy.

Thanks for the quick response, however the logger is still not behaving.

If I disable the logger sleeping, then the 5V switch on and stays on, If I allow the logger to sleep, even with P21=1, then the 5V will switch on during the test, then switch off when the logger sleeps, but on the next test will not come back on???

So I can get around the problem by not letting the logger sleep, but I thought the 5V should come back on each test is run (every 15 mins). At the start of the schedule I have the PWR5V=1, and I do not set it back to zero (PWR5V=0) anywhere, so does this mean that the 5V is only available if the logger doesn't sleep???

The problem I'm trying to solve is that when the logger wakes every 15 mins, I would like the 5V enabled to power a HIH-4000 humidity sensor, and then switch off at the end of the test, but it seems unreliable in switching the 5V on....Anymore thoughts??

Hi,

The 5 V output is derived from the analog power supply, so it will only be on if the analog section is powered.when Loggers is in sleep mode the Analog power system is turned off , when it wakes DT8x will wait for 50 ms to stabilize before it takes measurement . The reason it worked with 5 sec scan may be Logger never went to sleep and analog power system was on all the time.

You can try increasing the Measurement delay the default one is 10 ms. Measurement delay Specifies the settling time required before a sensor can be measured and it can be defined as a channel option.

Thanks
Regards
Lokesh