Eaton easyE4

10. easyE4 communication Connection to other devices
10.17 Modbus TCP
If no analog I/O is physically present (e.g., analog I/O smart modules missing or
faulty), the image table (values = 0) will still be delivered to the client. No check, no
error message.
*For an error message, it is sufficient if only one of the requested addresses is not
unlocked or is invalid.
**A read operation always returns consistent data from the image table, since this
data is protected from other modules by semaphores. In other words, as of this writ-
ing, there is no known criterion for a "read input registers" error in the server.
Write Single Register 0x06:
In the event of an error, Modbus TCP will send an error frame.
Fault Code
1 byte
0x90 ;Write Single Register
Exception Code
1 byte
02 or 03 or 04
Exception Code 02 = Target address is invalid, i.e.,
l
0 (the user keeps specifying addresses as one-based addresses)
l
Not defined* or
l
Un-enabled*
*For an error message, it is sufficient if only one of the requested addresses is not
unlocked or is invalid.
Exception Code 04 = Error when attempting to write to the register (marker word)**
**A write operation can always write consistent data to the image table, since this
data is protected from other modules by semaphores. In other words, as of this writ-
ing, there is no known criterion for a "Write Single Register" error in the server.
Values are only allowed to be written if all required addresses are valid and
unlocked.
Write Multiple Registers 0x10:
In the event of an error, Modbus TCP will send an error frame.
Fault Code
1 byte
0x86 ;Write Multiple Registers
Exception Code
1 byte
02 or 03 or 04
Exception Code 02 = Target address is invalid, i.e.,
l
0 (the user keeps specifying addresses as one-based addresses)
l
Not defined* or
l
Un-enabled*
Exception Code 03 = The number of registers is not >= 0x0001 and <= 0x007B
OR
Number of bytes != Number of registers x 2
Exception Code 04 = Error when attempting to write to the registers**
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