Modbus master to shac communication

Is there any known way of migrating a data set point from a separate Modbus Master into the SHAC?
I am now of the understanding that the SHAC is setup to communicate as a master unit.
I have a (SMA data manager) also acting as a master/client and communicating with SMA PV and battery inverters (slaves) in an off-grid situation and would like to send/poll/read 1 x register (Battery state of charge SOC) as a minimum.
For obvious reasons this would be a very useful byte of data to input into SHAC to help cbus manage both self consumption and night time energy use and also to broadcast to all EDLT's and Ipads.
Ive found Modbus master to master gateways but it seems expensive ($600) and a clumsy way to achieve what could be far simpler.
Any support in finding the right solution would be extremely appreciated.
Ash

Just thought a photo might help build some interest in finding a solution

 

As you have probably worked out, RS485 Modbus can only have one master. That means you need the master to write to the SHAC. I am not familiar with the SMA device, but at a glance it looks like it connects to all the devices via RS485 then collates it and presents it via it's own web page? Maybe look past the 485 Modbus side altogether. The SMA has it's own API to access the data - https://developer.sma.de/sma-apis.html although it may come with a fee.

 

Ok sounds simple. I think it's time to keep up the learning on this, I had previously never heard of an API.
SMA reopen tomorrow so I think my next step will be with them to see what their communications department suggest is the easiest way forward.
Im greatful for your help.
Ash

 

If you have no luck there, I have installed a couple of Moxa 485 to TCP modbus modules and got them working with my SHAC. TCP modbus has the benefit of multi-master so as long as the polling doesn't clash, it can be polled by multiple devices.

 

All is good, after many hours and not going to let it beat me I've come out on top.
Thanks