Controller Connections
Instruction Manual
147
takes care of all the protocol’s overhead and handshaking requirements.
The Expert Alpha controller supports the following public Modbus function codes:
01 (0x01) Read Coils
02 (0x02) Read Discsreet Inputs
03 (0x03) Read Holding Registers
04 (0x04) Read Input Registers
05 (0x05) Write Single Coil
06 (0x06) Write Single Register
15 (0x0F) Write Multiple Coils
16 (0x10) Write Multiple Registers
Please visit http://Modbus.org for more information about the Modbus fieldbus.
Use the following table to correlate the external PLC addressing to the controller’s inputs and outputs.
Memory Type
Controller I/O
Type
External PLC
Address
Data
Type
External PLC
Read/ Write
“1” Coil Input 10001 - 20256 Bit Read/ Write
“2” Input Output 20001 - 20256 Bit(s) Read
"3" Holding Register Input 30001 - 30256 Mixed Read/ Write
"4" Input Register Output 40001 - 40256 Mixed Read
“5” Force Single Coil Input 50001 - 50256 Bit Read/ Write
"6" Single Register Input 60001 - 60256 Mixed Read/ Write
“15” Force Multiple Coils Input 0F0001 - 0F0256 Bit(s) Read/ Write
"16" Multiple Register Input 100001 - 100256 Mixed Read/ Write
For Mixed Data Type the type of data depends on the user assigned input and output functions.
It is important to understand that the coils and registers use the same memory.