So I was fooling around with the RFTC Processor, trying to program a few things that need to read out inventories of Mek Machines. Long story short, it doesn't work.

In RFTC you have to define 2 sides when accessing an inventory:
First one defines where the external inventory is, in relativity to the processor (North, East...).
Second one defines from which side of the external machine, the processor tries to access an external machine and tries to read it's inventory. this can also be left blank, called "null side"

First problem is that Mekanism inventories can't be accessed without defining a access side (null side), this causes an RFTC program error.

When a side is defined, RFTC seems to be able to read the inventory, however it gets wrong information and always outputs that the inventory of the machine is empty.

McJty (author of RFTools) thinks that this is a bug on mekanism's side (McJtyMods/RFToolsControl#45):

Well that is a bug in Mekanism as it seems not to accept 'null' for side for the item handler and this is required. You can report that to mekanism.

As to why it isn't working otherwise, I also suspect Mekanism, as rftools control just uses the basic API from forge/MC for accessing items

I'll have to mention, that RFTool's inventory checker block and the inventory module for the screens work. I'll add that in the pictures as well as the RFTC program code I've used.

Code.txt