Re: [Apcupsd-users] issues with using MODBUS protocol on SMC1500I-2UC

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Hi All,

I am posting to the list regarding reports of MODBUS over USB issues.  
Recently, the NUT project integrated the modbus code into the NUT 
project and now supports MODBUS on APC and there's also been a few 
reports of issues on their forums.  So I decided I want to clear the air 
and (possibly) list a "reference setup" that works.

The UPS I have is a United States model SMT1500.  No C or anything after 
the model, just SMT1500.   This is an older UPS that has a manufacture 
date of 11-3-2012, I picked it up from a customer who was convinced it 
would be better to buy a new piece of crap APC UPS  (one of the all 
plastic BackUPS ones) instead of buying replacement batteries for the 
SMT (because that UPS takes those big batteries and they are so 
expensive)  You can't argue with stupidity.

Anyway the device came with no smartcard in the slot, and it just had 
the usual USB port and RJ48 port to plug the weird serial cable whatever 
into.  The front panel indicated under About that the UPS was running 
firmware version 8.4.  No indication of MODBUS support in the menus.

Note that according to archives online APC released an "earlier version" 
of the SMT1500 that won't take update firmware that has MODBUS.  But the 
highest firmware it used to take was version 5 and sinc emine was at 
version 8 I knew it was a later version.

I then took a Windows 11 laptop and downloaded and installed Powerchute 
Serial Shutdown (file pcss.zip) from APC's URL

Software Firmware Tool (apc.com) 
<https://www.apc.com/us/en/download/software-firmware/>

and ran the installer.  During the install it does a bunch of stuff, 
removing existing Windows USB power drivers, installing it's own 
drivers.  Then it gets to an autodetect section, at that time I plugged 
in the USB cable from the UPS to the laptop and it detected it and 
finished installation.  The software fires up a local webserver on the 
PC.  I logged in and verified that it was talking to the UPS and the UPS 
was communicating.  I also set the battery change date since I had just 
put in new batteries.  It's a VERY invasive piece of software.  I 
installed it to "purify and "Scheniderize" the computer so there would 
be no issues with the next step of updating the firmware.

Note that this is NOT the Powerchute personal edition - that software is 
still out there, here:

PowerChute Personal Edition | APC USA 
<https://www.apc.com/us/en/product-range/61934-powerchute-personal-edition/>

But its' pretty restricted in what it can do.  The Powerchute Serial 
Shutdown - which was announced here:

PowerChute Serial Shutdown is available to download - Schneider Electric 
Community 
<https://community.se.com/t5/APC-UPS-Data-Center-Enterprise/PowerChute-Serial-Shutdown-is-available-to-download/td-p/427283>

seems to be written the way it is because they intend on porting it to 
"other operating systems"  AKA  Linux.  There's also an

intriguing link here:

PowerChute Serial Shutdown Public Key for Linux RPM | Schneider Electric 
<https://www.se.com/us/en/download/document/APC_RPM-GPG-KEY-PCSS/>

but no other info on how to use it.

Next I downloaded the APC firmware update wizard, filename 
Smart-UPS_Firmware_Upgrade_Wizard_v4.3.6V2.zip from the URL How do I 
update the firmware of my SRT/SMC/XU/XP/SMX/SMT/SCL/SRC/CHS series 
Smart-UPS using the Firmware Upgrade Wizard? - APC USA 
<https://www.apc.com/us/en/faqs/FA279197/>

Note that this URL does not seem to be easily reachable from APC's 
byzantine menus and it also is not the URL that is referenced in a great 
many APC help messages on the APC forum. APC has been moving things around.

I then extracted it, went into Services on the laptop and stopped the 
Powerchute service.  Then I ran the firmware install wizard. It detected 
the UPS, and then selected a firmware for the UPS which it labeled 
"Version 15"  I then had to power down my servers and such, then it 
successfully uploaded the firmware to the UPS. The UPS screen stayed lit 
for about 5 minutes then the UPS shut off.  I then waited another 5 
minutes and powered up the UPS. Now, the About screen on the UPS said it 
was at firmware 15.

Note that there are 2 Readme files in the directory of the Update wizard 
one that says the firmware version is 4.3.6V2 and the other that says 
the version is 15.  However, in looking at the archives in the Wayback 
machine it appears that APC renumbered firmware because the SMT1500 unit 
was originally upgradable to firmware 9.4 which introduced MODBUS support.

The new firmware now had a MODBUS enable in the Advanced menu. You have 
to enable the Advanced menu from the front panel before you see the 
MODBUS listing.  I enabled it.  There was no other indication in the 
firmware that you needed to select the USB or Serial port or any of that.

I then unplugged the USB cable from the laptop and plugged it into my 
FreeBSD server running FreeBSD 12 64 bit with apcupsd 3.14.14 built on 
it, and modified the apcupsd.conf file to:

UPSCABLE  usb

UPSTYPE modbus

DEVICE

and restarted apcupsd.  It connected with zero trouble to the UPS.  Here 
is the output:

# apcaccess
APC      : 001,039,0909
DATE     : 2023-12-13 23:39:00 -0800
HOSTNAME : officeserver
VERSION  : 3.14.14 (31 May 2016) freebsd
UPSNAME  : APCUPS
CABLE    : USB Cable
DRIVER   : MODBUS UPS Driver
UPSMODE  : Stand Alone
STARTTIME: 2023-12-13 22:47:33 -0800
MODEL    : Smart-UPS 1500
STATUS   : ONLINE
LINEV    : 121.6 Volts
LOADPCT  : 23.4 Percent
LOADAPNT : 18.2 Percent
BCHARGE  : 100.0 Percent
TIMELEFT : 57.0 Minutes
MBATTCHG : 5 Percent
MINTIMEL : 3 Minutes
MAXTIME  : 0 Seconds
OUTPUTV  : 121.6 Volts
DWAKE    : 0 Seconds
DSHUTD   : 0 Seconds
ITEMP    : 25.2 C
BATTV    : 27.4 Volts
LINEFREQ : 60.0 Hz
OUTCURNT : 2.16 Amps
NUMXFERS : 0
TONBATT  : 0 Seconds
CUMONBATT: 0 Seconds
XOFFBATT : N/A
SELFTEST : OK
STATFLAG : 0x05000008
MANDATE  : 2012-11-03
SERIALNO : AS1244115771
BATTDATE : 2023-12-14
NOMOUTV  : 120 Volts
NOMPOWER : 1000 Watts
NOMAPNT  : 1440 VA
FIRMWARE : UPS 15.0 / 00.5
END APC  : 2023-12-13 23:39:27 -0800
root@officeserver:/usr/local/etc/apcupsd #

Here is the output of apctest:

# apctest

2023-12-13 23:42:30 apctest 3.14.14 (31 May 2016) freebsd
Checking configuration ...
sharenet.type = Network & ShareUPS Disabled
cable.type = USB Cable
mode.type = MODBUS UPS Driver
Setting up the port ...
Doing prep_device() ...

You are using a MODBUS cable type, so I'm entering MODBUS test mode
Hello, this is the apcupsd Cable Test program.
This part of apctest is for testing MODBUS UPSes.

Getting UPS capabilities...SUCCESS

Please select the function you want to perform.

1)  Test kill UPS power
2)  Perform self-test
3)  Read last self-test result
4)  View/Change battery date
5)  View manufacturing date
10) Perform battery calibration
11) Test alarm
  Q) Quit

Select function number:

In summary - once more on the list here we have to emphasize that the 
SMT models of the APC SmartUPS are the ones to buy.  Not SMC, nor 
BackUPS, or anything else.  Some of those will work with the USB-HID 
driver that will give reduced output, some may work with MODBUS some may 
work with MODBUS over just the serial port, who can tell.  Adam made a 
very large effort nearly a decade ago before getting the MODBUS contract 
with APC to write a MODBUS module to support some of those cheap 
BackUPSes that were coming with USB ports and there were a lot of bugs 
in the USB implementation on those cheap APC UPSes.  But nowadays APC is 
restricting the monitoring port on the cheap BackUPS to only the more 
expensive BackUPS devices so with a little more money you can get a 
SmartUPS so why mess with the cheaper models?

It would definitely be useful for more test reports to come in. I 
actually do have a fair selection of UPSes in my test library but the 
larger Enterprise-level UPSes are all SMT models.  Or they are the much 
older APC UPSes that do not have a digital front panel readout they just 
have the lights, and therefore speak the much older UPSLink protocol.

I'm glad that the NUT project decided that they had to copy over the 
modbus model to NUT.  It's what I have been hoping would happen for a 
number of years now.  I never liked their halfway-house solution of 
using a bridge driver to go from an apcupsd instance to NUT.  I don't 
know why they are having problems with MODBUS over USB unless the issue 
is they don't know precisely what they are doing, or they are testing 
with cheap-crappy APC UPSe not enterprise-quality APC UPSes.  I know 
that they follow this mailing list from time to time so maybe they will 
happen on this post.  NUT used to be Eaton's poster child but they then 
seemed to branch out into the lowest common denominator UPSes out 
there.  It's possible they are under the impression that non-Enterprise 
quality APC UPSes are just as good as the Enterprise gear and that was 
the impetus to incorporate MODBUS.

Anyway, if you have been having problem with MODBUS over USB, then try 
the latest APC Firmware updater at the link above.

And let the list know how things work out.

Ted

On 1/31/2022 12:26 AM, Daniel Dinnyes wrote:
>
> I am using a APC UPS model SMC1500I-2UC 
> <https://www.apc.com/shop/ph/en/products/P-SMC1500I-2UC>, with latest 
> firmware (v04.1), and *apcupsd version 3.14.14*.
>
> I have cP.1 setting 
> <https://manuals.plus/apc/smart-ups-c-uninterruptible-power-supply-manual.pdf> 
> on the UPS (enables MODBUS protocol), and using UPSTYPE MODBUS setting 
> in apcupsd.conf.
>
> I am experiencing the following issues:
>
>   * getting constant broadcast messages about connection lost / restored.
>   * apcaccess doesn't show many of the device specific parameters
>     (e.g. SERIALNO, MODEL, FIRMWARE, MANDATE)
>   * apcaccess shows wrong values for BCHARGE (1.7% instead of 100%),
>     and doesn't show TIMELEFT. Since MBATTCHG is 5% and MINTIMEL is 3
>     minutes, not recognizing those is possibly responsible for the
>     *immediate shutdown when switching to battery power*.
>
> These problems are very similar to the ones described here 
> <https://community.exchange.se.com/t5/APC-UPS-Data-Center-Backup/smt1000rmi2uc-and-modbus-protocol/td-p/297253>. 
> As the solution recommends in the thread, when I disable MODBUS 
> communication protocol on the UPS, and change back the apcupsd config 
> to UPSTYPE USB, and restart the daemon, the above issues are resolved. 
> After this, switching to battery power doesn't cause immediate 
> shutdown, and the BCHARGE, TIMELEFT, TONBATT, CUMONBATT, XONBATT, 
> XOFFBATT parameters show up, and get updated as expected.
>
> The problem what remains still is that using USB instead of MODBUS, 
> |apcaccess| doesn't return certain operational parameters (e.g. LINEV, 
> MINLINEV, MAXLINEV, OUTPUTV, OUTCURNT, LINEFREQ, LOADPCT, AMBTEMP, etc).
> I know that the UPS itself supports these parameters, as I can see 
> them through SmartConnect on the APC online portal.
> Also, most of the operations are not working with |apctest| when not 
> using MODBUS protocol.
>
> --
> Regards,
> Daniel
>
>
>
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