The Anybus modules (like the M40 series) adapt between some Anybus-defined representation of data stored by the embedded application and some external field bus.
Let’s take Modbus/TCP for example. It provides access to 64k registers, each has 16bit. There are no 32bit integer numbers or floating point numbers - just 16 bit integers. However, Anybus supports 32bit integers and floating point numbers.
Somehow, the Anybus module provides some mapping between the two worlds. However, I can’t find any description of this mapping. Does Anybus use 2 modbus registers for each 32bit integer, if so, which endianess? What about busses other than Modbus?
What if I use an index (Anybus calles them instance numbers) of 39123? That works with Modbus (cause it support 64k registers) but is there some bus out there that only support 4096 registers for example? How would an Anybus module provide access to such an instance number? Or is Anybus limited to busses which support 64k registers and more?
I would appreciate some documentation giving a brief overview of the busses/interfaces that are supported by the Anybus M40 family and then some description of the mapping of the data model and notions on the Anybus side (ADIs, 32 bit integers, floats, etc.) to the data model and notions on the interface side (e.g. Modbus registers, 16 bit integers).
Does Anybus support all features (structured types) on all busses? Are there any drawbacks of certain Anybus features when they are used with certain busses ?
Does Anybus/HMS provide such a document?
Update: meanwhile I have found the “Network Guide - Modbus-TCP” which answers many of my above questions. The Modbus module supports up to 3800 ADIs, for each ADI, 16 modbus registers are reserved (can be configured).
What I haven’t found however, is an overview document. Right now, when I still can change the layout of my ADIs, I need to get an overview of the restrictions of all modules in the M40 series. The Modbus module seems to have quite severe restrictions (by default, at most 32 byte per ADI, at most 3800 ADIs).