SMT750IC / Modbus-over-TCP... how?

[Occamsrazor]

Hi,

I bought an SMT750IC and have it up and working with SmartConnect which is actually better than I thought it would be though still very limited. Updating the firmware from the cloud was useful, especially as I have no Windows machine.

I also got it working with APCUPSD using the included USB cable and ModBus connected to a Mac, the working apcupsd .conf was this:

UPSCABLE usb

UPSTYPE modbus

DEVICE

Though seriously, why a double-ended USB-A cable and not the usual USB A>B ????

Anyway, in the latest Firmware 4.1 release notes of the SMT750IC it says "SMT series now supports Modbus over TCP" and they are talking about the embedded SmartConnect port.

And in the updated user manual it now details the options that are in the advanced settings of the UPS:

- Slave ID 1 1- 223 Sets the Modbus slave address of UPS

- Ser+USB - Enables or disables UPS Modbus protocol over serial and USB ports [This was by default disabled, I had to enable it to get Modbus working over USB to apcupsd]

- TCP Protocols - Enables or disables UPS Modbus TCP/IP protocol provided by the embedded SmartConnect port.

• Disable: Disables UPS Modbus TCP/IP protocol
• Read-Only: Modbus master over TCP/IP protocol is only allowed to get UPS status.
• Read-Write: Modbus master over TCP/IP protocol is allowed to get UPS status and control the UPS.
• The port number of UPS Modbus TCP/IP protocol is fixed at 502

OK, so according to this it is now opening MODBUS protocol through the SmartConnect ethernet port. And APCUPSD understands MODBUS protocol.

So is there any chance to connect APCUPSD to the UPS over the network to the SmartConnect port using MODBUS protocol? If so any idea how? If not, then how would you use this Modbus-over-TCP feature?

Thanks.

[Occamsrazor]

Bump... anyone?

[PVasileff]

Up 2022, Any ?

[Occamsrazor]

@PVasileff- I'm afraid I never got anywhere with this. I did ask on the apcupsd mailing list but the suggestions for how to investigate it were way too technical for my capabilities, and as there appears to be almost no documentation from APC I pretty much gave up.

[TonKei]

Hi @Occamsrazor 

I can provide you with part of the information here, since we do not support APCUPSD, I am staying away form that part of the conundrum.

For the unit itself, activating Modbus TCP as per the manual should be pretty straight forward.

I did manage to dig up the register map for the units up as well, and you can find it here -> https://www.se.com/us/en/download/document/SPD_LFLG-A32G3L_EN/

As mentioned, how APCUPSD handles modbus TCP, or if it is even supported, is beyond my knowledge, so I will need to pass on that.

But I hope the register map can be a step in the right direction for you.

Best regards

Tonny