[Nut-upsdev] driver for IVT SCD solar controller ?

Arjen de Korte nut+devel at de-korte.org
Thu Jul 30 20:17:34 UTC 2009

Citeren Rainer Fuegenstein <rfu op kaneda.iguw.tuwien.ac.at>:

> 1st execution:
> [root op test drivers]# ./ivtscd -DDDD -a ivtscd
> Network UPS Tools - IVT Solar Controller driver 0.01 (2.4.1-1891)
> Warning: This is an experimental driver.
> Some features may not function correctly.
>    0.000000     debug level is '4'
>    0.002857     send: F
>    0.388363     read:
>    0.388853       \_: (42 bytes) => 00 52 3a 31 32 2c 31 32 3b 2d 20  
> 33 2c 38 3b 31 37 3b
>    0.389507      31 32 2c 30 31 3b 31 32 2c 36 32 3b 2d 20 36 2c 33  
> 3b 20 30 2c 31 3b 0a
>    0.390166     Parsed -1 parameters from reply
>    0.390670     IVT Solar Controller not detected

OK, that should be fixed now. We also skip over NULL bytes in the  
reply in the latest version from the trunk.

>> It could be that we're beating the SCD to death by doing a query twice
>> right after another. This should be resolved once the driver has
>> started up and it polls once every 2 seconds.
> yes, it looks better now, except for first null byte in the first run.
> (it's running for five minutes now and shows reasonable data).

The problem is probably that the controller can't transmit and receive  
at the same time (half duplex). From the timestamps it looks like it  
is still sending a character while we're already sending a new command  
(which is then ignored). Adding 'sleep(1)' between sending a command  
and reading back the reply should fix that.


> unfortunately, none of my (working) laptops has a serial port anymore.
> I'll need to read into this ground loop problem ...

For this I keep a USB to serial converter handy. My laptop doesn't  
have a serial port either. Models supported by the kernel are not too  
hard to find nowadays.

Best regards, Arjen
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