Rockwell Automation AADvance Controller Configuration Guide - Manual (Page 227)

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Document: 553633
ICSTT-RM405f-EN-P
Issue 07
9-41
Write Multiple Coils
Function: write
Function Code = 15
Address Offset: COIL_STATUS_ADDR
Data Type: boolean
Fixed Length: 9
Varbyte length: 6
Purpose: Forces each coil in a sequence of coils to either ON or OFF in a remote
device.
Write Multiple Registers
Function: write
Function Code = 16
Address Offset: HOLDING_REG_ADDR
Data Type: analogue
Fixed Length: 9
Varbyte length: 6
Purpose: Writes a block of contiguous registers (1 to 123) in a remote device.
Modbus Slave Link Control and Status Registers
Every Modbus slave link object has a pair of registers (holding registers), which allow
the application to control the link, and to retrieve status information. The registers are
a 'control register' and a 'status register'. Each register is located at a unique address
— the Control Variable Address and the Status Variable Address.
The use of the registers is optional. If you want to use a register, you have to declare a
variable for it in the application Dictionary; and also specify the address in the holding
register map.
Modbus Slave Link Control Register
The application can use the control register to control a specific slave link. If you do
not specify a control variable address, then the link is enabled automatically when the
controller is started. The variable in the application Dictionary has the functions
listed in the table.
Table 31: Modbus Slave Control Register