3x Modbus Addressing Unity PRO for M580

I have a confusion regarding modbus addressing that it looks like in unity PLC we can only access 1x (%Mx) and 4x (%MWx) registers and we have to copy discrete input bits (0x - %Ix) to %Mx variables and analog inputs (3x - %IWx) to %MWx registers to read them on modbus.

It appears that Unity PLC's inputs (3x address) aren't automatically linked to modbus addresses => Whole memory area 3x / 4x is used for %MW address variables only. So if we try to read e.g. 300001 address from Unity, we won't see first's analog input register, instead we will see value of first memory word, which is %MW0 and it appears it is same for (400001 & 300001). As per manuals %IW = 3x memory area but it seems it is not possible to read either the %I or %IW references. Every type of I/O references must be moved to %M and %MW references for modbus access.

I have a as-built SCADA list from our client which cannot be modified. This list contains variables on both 3x address and 4x address. If I use %MW for both address types then there will be overlap between variable

Kindly advise resolution If Any.

http://www.plctalk.net/qanda/showthread.php?t=107286

http://www.plctalk.net/qanda/showthread.php?t=89342

The above threads may help you out.
Regards,

I dont think you can read directly the Discrete input or analog input channels. Like you say you have to copy analog to %mw. You can also copy the discrete inputs to %mw.x if your driver cannot read the %m.
I think 3x registers are for %m and 4x registers are for %mw. To make things easy i would copy analogs to %mw and discretes to %mw.x

Hope this helps

Thanks for the replies. I have some understanding and clarity now.