Opta real time clock

Official Hardware Opta
1

Does anyone have any information on how to read and set the real time clock on the Arduino Opta PLC please?

I've seen two variables:
sysTimer
sysTimerHiRes are these anything to do with the RTC?

2

Hello @MarkWigley,

Take a look in the RTC section of Opta's User manual; there is an example of how to set Opta's RTC using an NTP server. Let me know if this helps!

3

Hello @jabagur

Thank you for your help.
With your help I managed to get it to work!

I wanted to set the Opta PLC RTC from a Unix Epoch Time. ie 1701633230

set_time(1701633230); // This set the PLC RTC.

I then needed to extract just the Hours and Minutes.

    time_t t = time(NULL);
    struct tm * ptm;
    ptm = gmtime ( &t );

    ptm->tm_hour;
    ptm->tm_min;

Thank you
@MarkWigley

4 Likes
4

Hi, we want to use Opta's RTC as a backup timer for when we lose power. The datasheet says it can live for ~10 days without power.
I set the time and then kept the PLC off. After 2 weeks, I turned it on and read the time. It had counted time for almost 2.5 days and then stopped at that time. I expect it to reset to 0 if it has not been running, otherwise we would just have a wrong time and we won't know that it is wrong.
Is that how it is supposed to be? It does not last 10 days and it also does not set a flag or reset the time when it finally loses power?