Control.com - Nerds in Control

I have 4 questions:

1)The Exception Coils are included in the normal coils or are independent coils?

2)The Diagnostic Register is included in the holding registers or is an independent register?

3)The Counters are 16-bit Registers included in the holding registers or are independent registers?

4)The answers to the questions 1-3 are device dependent or are the same for every modbus device?

All are device dependent. Modbus Registers are 16 bit register values that contain a binary value that can represent anything.

> All are device dependent. Modbus Registers are 16 bit register values that contain a binary value that can represent anything. <

Yes, but for example in the modicon 884 controller the coils 761-768 are used for the exception status coils.

My question is: is possible that any modbus salve device has 65536 coils and in addiction 8 exception status coils? Because in the modbus specification there are no obligation to use the coils in the range 0-65535 for the "exception status coils".