AMCI NEXUS NX2A4E2, User Manual

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Modbus TCP Protocol
M
ODBUS
TCP C
ONFIGURATION
69
Supported Modbus Functions
Table T5.2 Supported Modbus Functions
Table T5.2 above lists all of the Modbus functions supported by an NX2A4E2. AMCI supports all of these
functions so that you can control the unit as you see fit. However, if you are looking for the easiest way to
interface with your unit, then you only need to use the
Read/Write Registers function, which is function code
23.
Each NX2A4E2 buffers the data that is sent to it over the network. If you use the Read/Write
Registers function to write data to the unit, the data read with that command will not contain
the response to the new write data. The response to the new data will be sent with the next data
read.
Supported Modbus Exceptions
Table T5.3 Supported Modbus Exceptions
Function
Code
Function Name
SD4840E2
Register
Addressing method
1 Read Coils OUTPUT Bit:Addresses starting at 16,384
2 Read Discrete Inputs INPUT Bit:Addresses starting at 0
3 Read Holding Registers OUTPUT & INPUT
Word: Out Regs.Starting at 1024
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In Regs.Starting at 0
4 Read Input Registers INPUT Word:Addresses starting at 0.
5 Write Single Coil OUTPUT Bit:Addresses starting at 16,384
6 Write Single Register OUTPUT Word:Addresses starting at 1024
15 Write Multiple Coils OUTPUT Bit:Addresses starting at 16,384
16 Write Multiple Registers OUTPUT Word:Addresses starting at 1024
22 Mask Write Register OUTPUT Word:Addresses starting at 1024
23 Read/Write Registers INPUT/OUTPUT
Word: Out Regs.Starting at 1024
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In Regs.Starting at 0
Code Name Description
01 Illegal function The NX2A4E2 does not support the function code in the query.
02 Illegal data address The data address received in the query is outside the initialized memory area.
03 Illegal data value The data in the request is illegal.