[Nut-upsdev] APC protocols and drivers (was: Documenting the NUT driver-qualification process)

[Arnaud Quette]

Hi Ted

there was a drift from the initial topic.
worth a new thread!

2014-07-27 9:13 GMT+02:00 Ted Mittelstaedt <tedm at mittelstaedt.us>:

> On 7/26/2014 12:18 PM, Arnaud Quette wrote:
>
>> Hi Eric,
>>
>> sorry for the lag, summer time...
>>
>> I'm first seconding Charles comments
>>
>> 2014-07-09 12:31 GMT+02:00 Eric S. Raymond <esr at thyrsus.com
>> <mailto:esr at thyrsus.com>>:
>>
>>
>>     I think the time for me to get involved in NUT documentation has come
>>     again.
>>
>>
>> welcome back
>>
>>     Late last week I had to buy a UPS under time pressure.  The Eaton unit
>>     that thus project gifted me with in 2006(?) died during a severe
>>     thunderstorm watch, so it was off to MicroCenter to get a replacement
>>     pronto.
>>
>>     I wound up buying an APC BN700MC.  It was what they had in the
>>     performance range I needed.  The removable battery door was pleasing.
>>
>
>
>
>>     Based on the experience, I have updated the UPS HOWTO:
>>
>>     http://www.catb.org/esr/ldp/UPS-HOWTO.html
>>
>>     The bad news, however, is that (a) this is not a NUT-supported device,
>>
>>
>> I've logged an entry for the APC Modbus:
>> https://github.com/networkupstools/nut/issues/139
>>
>>     and (b) the (poorly documented) NUT process for discovering and
>>     customizing a driver failed at the first step.  Running upsstart
>>     gave a driver fail message containing no clues as to how to recover.
>>
>>
>> yup, definitely room for enhancement!
>> I've got some ideas, beside from the obvious need to improve the
>> documentation, that I'll like to discuss.
>>
>>     This is definitely USB and probably a fairly generic hidups device.
>>     There is no good reason for customizing a driver profile to be
>>     so difficult.
>>
>>
>> well, I'm unsure since I'm just opening this "APC Modbus Pandora box"
>> but if I understand correctly, your new unit is a microlink one.
>>
>
> MAYBE.
>
> HIS UPS is a BackUPS not a SmartUPS.  Originally the APC BackUPS DID NOT
> SUPPORT any Smart protocol (the original UPSLink protocol)
>
> But over the years it's been observed that APC has somewhat "fudged" on
> the BackUPS UPSes.  Newer ones did appear to implement the UPSlink
> protocol over USB.
>
> Microlink protocol is officially only for APC SmartUPSes.  Officially,
> what your supposed to get with a BackUPS is dumb signalling only.  But,
> with the newer BackUPSes that have USB output, some seemed to act like
> SmartUPSes even though they were not.
>
> APC has very much blurred the line on the model BN UPSes.  These are the
> APC UPSes that look like an oversized power strip.  That's the one that he
> has.  They seem to have dropped monitoring ports completely on these UPSes
> that are under 700VA in size.  They used to make monitoring ports
> on these UPSes all the way down to 350VA.  But the current models, only
> the 700VA unit like the one he bought, still support the monitoring port.
>  That port is the special wide RJ45 that has 10 conductors not 8.
> It is selectable between serial and USB depending on what cable is used
> with it.
>
>
>  though the serial version should be Modbus only,
>>
>
> There is no "serial only" APC UPS that supports Modbus, in fact no APC
> smart UPS since the Microlink protocol was implemented has been "serial
> only", all have been dual-use  Serial and USB.
>
>
>  I can't say at first if
>> the USB ones implement if full Modbus over HID or any other mean.
>> I would need traces to give more info.
>>
>>
> The BackUPSes with USB ports might implement full UPSlink over HID.
>
> Or they might implement Microlink over HID
>
> Or they might implement nothing like either of that.
>
> But they definitely don't implement Modbus.
>
> It is best I think to refer to BackUPS and SmartUPS in the documentation.
>  Please do not refer to APC UPSes in a generic fashion. And please don't
> assume that any APC BackUPS implements any particular
> protocol over USB or Serial unless you have directly tested it.  APC
> BackUPS upses are the "cheap, poor relations" and are for consumers and
> penny-pinching businesses that are too cheap to spend a couple hundred
> bucks on decent gear.  Purchasers who want full functionality should be
> encouraged to buy an APC SmartUPS.
>

thanks for these details, still too blurry for the little time I currently
have!
my aim there is not to understand APC offering. I don't have time nor
interest in that!
my aim is simply to have people happy, which generally means supporting
their unit, so developing code. period.

So, if someone (maybe you):
1) can clarify APC situation WRT protocols (both serial and USB ; microlink
/ UPSLink / whatever-nameLink)
2) and has access to unit(s) to provide sniff

I can check to develop some generic code in "blind mode" (no access to
devices), for modbus or else, that also supports APC.

cheers,
Arno
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