Re: How to calculate checksum (three ASCII values) when using streamdevice

[LiangChih Chiang via Tech-talk <tech-talk at aps.anl.gov>]

Hi, Thanks Zimoch,

>By default checksums are written in binary. But with the modifier + you can
>change that to decimal: %+<sum>.
>(With %0<sum> it would be hexadecimal.)

Thanks. I works.

checksum calculation example:
Command: 1220074002=?110
ASCII: 49 50 50 48 48 55 52 48 48 50 61 63
sum and modulo 256 = 110

Response: 1221074006539212045
ASCII: 49 50 50 49 48 55 52 48 48 54 53 51 57 50 49 50
sum and modulo 256 = 045

>Wait, this looks like a typo: (20-12) is not -8.
>You need (12-20) to get that.

Yes. It's a typo. My mistake.

>>539212: -> 5.392x10^(20-12) hPa = 5.392x10^-8 hPa
>If you wonder how to parse that, try the following:

Your parsing method is better than mine. Thanks

On Mon, Aug 17, 2026 at 4:41 PM Zimoch, Dirk <dirk.zimoch at psi.ch> wrote:

On Mon, 2026-08-17 at 08:36 +0000, Zimoch, Dirk via Tech-talk wrote:
> > > > 539212: -> 5.392x10^(20-12) hPa = 5.392x10^-8 hPa

Wait, this looks like a typo: (20-12) is not -8.
You need (12-20) to get that.

> On Mon, 2026-08-17 at 08:26 +0000, Zimoch, Dirk via Tech-talk wrote:
>
> If you wonder how to parse that, try the following:
>
> %#/(.)(...)(..)/\1.\2E-\3/%f

%#/(.)(...)(..)/\1.\2E\3/%f

>
> This is a regular _expression_ substitution that groups the input into 1/3/2
> characters and inserts . and E-
>  539212 -> 5.392E-12

539212 -> 5.392E12

>
> Then then let the ai record scale the value with 1e20:
> field(ASLO, "1e20")
>

Scale with 1e-20:
field(ASLO, "1e-20")