Serial communication to APC Smart UPS SMX3000RMHV2U

[BillP]

Hi,

I am trying to establish a serial communication to APC Smart UPS model : SMX3000RMHV2U by using the included serial cable. I used the following parameters from "Checking UPS Communications on Windows" manual: - Baudrate : 2400,8,N,1 I sent a "Y" character, the UPS returned nothing which according to the manual should respond with "SM" characters. Then I send another "A", again the UPS returned nothing. This UPS and cable are fresh out of box and I tested and can confirm that my serial port is working. Any idea what might be the issue here — settings and command wise? Thank you!

[BillP]

The way you're trying to talk to this UPS is only applicable to older models that begin with model prefix SU, SUA, SUM, SURT, SURTA and a few select others. You won't be able to talk directly to this UPS as it speaks a different language.

The following application notes may help you to understand the different options for different UPS models and how you may be able to communicate with them:

www.apc.com/whitepaper/?an=176 (these UPSs can talk Modbus which can be used for custom applications)

www.apc.com/whitepaper/?an=181 (outlines different communication options for Smart-UPS in general)

www.apc.com/whitepaper/?an=178 (covers USB HID implementation if USB is an option for you)

[BillP]

Hi Angela,

Thank you for the whitepapers! I managed to drill down to document #18[1] which said it supports SMX model. What I am trying to do is quite simple — to connect a microcontroller to this SMX Smart-UPS and retrieve on battery / main power loss status, then proceed to shutdown the equipment if the UPS is on battery. The microcontroller I am using can be triggered through RS232 signal and a relay. But since this SMX Smart-UPS comes with a Serial port, I thought it might work interfacing it using it.

Coming back to document #18, specifically on page 7 and 8, it says something about Power Fail signal with Output Type 1 which indicates AC Power Failure. I think that is close to what I need. Do you have more info on this section?

[1] http://www.apcmedia.com/salestools/MPAO-9E5RB5/MPAO-9E5RB5_R1_EN.pdfnVL4u2WRpyJfcwZiAblhLQ%3D%3D.png

[BillP · Accepted solution]

Hi Angela,

You can ignore my previous message.

Eventhough I could not talk to the SMX UPS using serial connection directly, now I was able to measure pin 9 and 7 voltage of the electrical signals on the same serial port. When the UPS is running on battery, it produced +5V consistently through these pins. And when the UPS runs off main AC power, it produced -5V. This way, I can integrate the voltage measurement to the microcontroller to shutdown equipment.

Thank you again for the whitepapers!

--

Ed

[huyhuynh]

Hi. I'm working on the exact same setup. I'm still trying to figure out how to check on the status of the UPS. I know we can use the serial that came with the UPS, Would you mind sharing with me your setup? I know you used a microcontroller to do so. I'm connecting the serial cable directly to my computer and use LabVIEW to see the states of the serial cable. However, the states don't seem to change at all when I unplug the UPS cable. I'd really appreciate it if you can share with me your setup. Thanks!