Smart UPS SMT750IC serial cable communication

[OKi]

Hello everyone,
I'm trying to connect the SMT750IC UPS to a machine IPC (still running the old Windows XP or Windows 7 operating system!) via serial port.
The UPS is connected to the original APC communication cable (940-0625A) and a free COM port (2400,8N1) on the IPC.
Unfortunately, a serial connection is not possible because the new UPS is not recognized at all.
The previous APC SC420I UPS, however, was able to communicate with the IPC without any problems.
Does the new SMT750 UPS require a special driver?
Thanks and best regards,
Oli

[Teken]

There are three serial ports on the SMT which are USB A, RJ50, RJ45 Smart Connect.

Insure the serial cable is not connected to the (Green) RJ45 Ethernet port as there is no local access on this.

There can only be one serial connection at any given time so no USB A & RJ50 connection.

Its unclear to me if you’re using APC Power Chute (PCBE / PCSS) software or something else such as APCUPSD / NUT / Other etc?!?

If this is the legacy PCBE try connecting via USB and report back the results. Often times PCBE needs to be uninstalled and reinstalled for the new system to be detected.

You may also try PCSS to see what happens and report back your results.

Questions Ask . . . 👍

[OKi]

Hello Teken,

Thank you for the quick response.

The serial cable (940-0625A) is connected directly to the RJ50 serial port.
No other interface cables are connected.

Additional software, such as APC Power Chute (PCBE/PCSS), is not installed, as this is unfortunately no longer available on the Schneider Electric website for the Windows 7/XP operating system.

Only the following operating systems are supported with the current version:

- Microsoft Hyper-V 

- Windows 10 

- Windows 11 

- Windows Server 2019 

- Windows Server 2022

Unfortunately, this is required for an older machine.

Is the PowerChute Business Edition or PowerChute Serial Shutdown also available for download for older operating systems?

 

[Teken]

I suggest you reach out to APC Technical Support to see if they still have a copy of PCBE for Windows 7 / XP.

You may also consider these free applications to see if they work: NUT / APCUPSD

Can you expand on how the previous APC UPS and IPC system was interconnected as this was unclear in your initial post.

As it comes across as Power Chute Software was installed prior but doesn’t see the new SMT750?

Or that you were using the native Windows (UPS) Power Management to communicate with the SC420??

As a reminder there are three other options to interface with the new UPS. The green RJ45 Ethernet port connects to the subscription based APC Smart Connect Cloud Hosted Service.

You have a six months trial to see if it meets your needs. The other preferred option is to install a NMC (Network Management Card) into the Smart Slot for complete local access and management of the new SMT750.

Questions Ask . . . 👍

[OKi]

I had actually already contacted APC support, but unfortunately, they were no longer able to provide me with older software from PCBE.
Thank you for the tip about the free APCUPSD application.
Although it showed a connection in the status window (visible by the time), I was unable to establish a connection using this software.
The old SC420I UPS communicated via Windows' own power management (UPS).
Unfortunately, the UPS must be connected to the PC via a serial port so that the corresponding COM port can be selected.
The USB connection unfortunately didn't work either (only one USB cable was plugged in).
I had, of course, configured the "apcupsd.conf" accordingly:

For a serial connection:
UPSCABLE smart
UPSTYPE apcsmart
DEVICE COM3
etc. ...

For a USB connection:
UPSCABLE usb
UPSTYPE usb
DEVICE
etc. ...

Could it also be related to the serial interface cable?
I think I read that the 940-0625A cable only supports Microlink.
The APC SMT750IC uses Smart Signaling, which requires a special APC serial cable.
Two other cables were specifically mentioned here:
- APC 940-0024C
- APC 940-1524D
(Generic straight-through serial cables do not work - the pinout is different!)

[OKi]

I had already contacted APC support, but unfortunately, they were no longer able to provide me with older software from PCBE.
Thank you for the tip about the free APCUPSD application.
Although it showed a connection in the status window (visible by the time), I was unable to establish a connection using this software.
The old SC420I UPS communicated via Windows' own power management (UPS).
Unfortunately, the UPS must be connected to the PC via a serial port so that the corresponding COM port can be selected.
The USB connection unfortunately didn't work either (only one USB cable was plugged in).
I had, of course, configured the "apcupsd.conf" accordingly:
For a serial connection:
UPSCABLE smart
UPSTYPE apcsmart
DEVICE COM3
...
For a USB connection:
UPSCABLE usb
UPSTYPE usb
DEVICE
etc. ...
Could it also be related to the serial interface cable?
I think I read that the 940-0625A cable only supports Microlink.
The APC SMT750IC uses Smart Signaling, which requires a special APC serial cable.
Two other cables were specifically mentioned here:
- APC 940-0024C
- APC 940-1524D
(Generic straight-through serial cables do not work - the pinout is different!)

[Teken]

The new system comes with the correct serial cable.

Why aren’t you using it vs the existing one??

[OKi]

The UPS was purchased directly from Schneider Electric or APC.
Unfortunately, the original packaging didn't include any interface cable.
After I informed APC support that the UPS must be connected via a serial interface, they specifically recommended this cable (940-0625A).
Could you please tell me which serial cable is nomally included as standard?

 

[Teken]

That would be the correct RJ50 -> DB9 RS-232 Serial cable.

I would suggest you adjust / check the COM Port settings and play around with the baud rate and report back the results.

Otherwise I would review the APC USB FAQ and try some of the action items related to Windows Drivers / APC Power.

Questions Ask . . . 👍

[OKi · Accepted solution]

A quick update regarding the serial connection problem.

Unfortunately, I had to wait for an ordered expansion card.

APC Level 2 support contacted me.

The SMT750IC uses Microlink for communication, while the SC420I used UPSlink.

Microlink is a proprietary communication protocol developed by APC around the time of its acquisition by Schneider Electric.

UPSlink, on the other hand, was developed by APC in the 1990s and is now publicly documented.

The solution is to use a SmartSlot expansion card, type AP9620, which is installed in the UPS to upgrade the SMT750 to UPSlink.

With this SmartSlot card, AP9620, communication with the machine computer finally worked.

The AP9620 kit also includes the corresponding serial connection cable (DB9 RS-232 -> DB9 RS-232).

I would still like to thank Teken for the support and suggested solutions.