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CHG Terminal Measurment

Nicolas Jan 2, 2021 07:43 AM

first of all, I wish you a happy new year 2021.
I am a new user of a CR300.
I power the CR300 through an external power supply (24VDC). I would like to issue an alert when the external power is lost. Is it possible to read the voltage across the CHG terminal ? An other idea ? Thanks in advance,


smile Jan 3, 2021 03:06 AM


do you not have a battery?


Nicolas Jan 3, 2021 03:15 AM


than you for your feedback. yes, I use a battery, I wanted to stop the measurements (and transmission) in the event of a power cut (to prevent the battery from discharging too much and that gives me time to resolve the problem)



smile Jan 3, 2021 05:36 AM

However you could use a resistor pair to make a divider and reduce the 24V to 5V and then through an analog channel, measure the recharge voltage.

Or simply even power a relay with 24V and use the normally open contact and use a digital port or analog channel and as long as the contact is closed the 24V are present.

Then with "if" programm activate an allarm


Nicolas Jan 5, 2021 01:12 AM

Hello, sorry for the late return but my posts remain "under review" for a long time. Yes, that's what I thought I would do if I couldn't find a "software" solution, which doesn't seem to exist.
A big thank you for your return.

Have a good day,


smile Jan 5, 2021 07:08 AM

if you want to do a sw only check, it might be quite certain, see the battery voltage ONLY starts to drop, this happens if the charger does not charge.

Usually under charge the battery voltage is 13.8 ... 14V or more, while without charger it soon drops by at least half a volt and then slowly only begins to go down.

Obviously "slowly" depends on what powers the battery and how much its capacity is.


Nicolas Jan 6, 2021 09:30 AM

Does cellular communications work through the USB port? as the battery does not have to be on continuous charge, I could use a 12V to 5V converter and power through the USB port ... VBatt would drop to 5V ...


smile Jan 10, 2021 04:09 AM


cellular connection through the USB port? never read anything about it. I believe the USB port is specific for PC connection which has drivers, a modem cannot. Moreover, the modem and the logger are 2 devices that interface to the PC and therefore cannot talk to each other.

Nicolas Jan 10, 2021 07:39 AM


With only power supply via USB connector the cellular modem is effectively not active.

thank you for your advice


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