DM42- clock losing time

[Walter]

The clock in my car (optionally) takes the time from DCF77, a radio station controlled by PTB. Thus, exact time all year round incl. DST - works like a charm.

[TwoWeims]

Great Idea!
Just add wheels and an antenna to the DM42 and problem solved...

[DA74254]

Great Idea!
Just add wheels and an antenna to the DM42 and problem solved...

[keithdalby]

Just add wheels and an antenna to the DM42 and problem solved.

Surely that would just begin a long, tedious discussion about the accuracy of the odometer though?

[TwoWeims]

Just add wheels and an antenna to the DM42 and problem solved.

Surely that would just begin a long, tedious discussion about the accuracy of the odometer though?

[RNav]

Crunching numbers... DM42.
Keeping Time... Omega Speedmaster.
Smart people debating the accuracy of a CRYSTAL 32.768kHz, ±20ppm (40ppm variation) IC... PRICELESS!

rps20190522_212254.jpg (222.52 KiB) Viewed 4949 times

[jthole]

I bet the DM42 (and thus the DM41X) keeps better time than the Speedmaster though!

[x55]

What about colour screen, GPS, wifi and stereo speakers?

My first electronic calculator was an over-pocketsize four-banger with a nixie tube display. It was a very expensive impulse buy while I buying a cheaper (!) Sinclair audio amplifier. The amplifier carried a little "STEREO" sticker. I knew that because it had a "Balance" knob, so I peeled the sticker off the amplifier and put it on the calculator. Electronic amplifiers were still very new but getting to be generally recognisable. Most of the visitors who saw it asked, "Oh - is your calculator a stereo model?" I'd answer, Yes" whereupon they'd go very quiet while they looked at it carefully for several seconds before changing the subject. Highly recommended.

These days, a way of getting NMEA sentences from an external GPS into DM42 storage (matrix?) or even one at a time into the X-register would open a lot of realtime navigation/surveying program possibilities.

[x55]

When I bought my DM42, I could have sworn there was a note about an RTC or accurate clock.
Jerry

My downloaded destructions say:

3.9. RTC correction
Note that to apply RTC correction you have to know (measure and calculate) ppm drift of calculator
clock first.
Use following steps to apply clock frequency correction. ...

Maybe that's a recent addition?

[whuyse]

Regarding the RTC correction: if your DM42 clock is fast (i.e. it shows a later time), should the factor C be positive or negative? It's not clear from the description, so I have a 50/50 chance of being right, meaning I'll be wrong
Werner