Messages

Use the appropriate

Modbus

command depending on the address range and the number of addresses. The

T8151 Communications Interface

supports these commands:

Address Range		Size	Direction	Modbus Command
Low	High			Type	Code
1	9999	1	Read	Read Coil Status (Read Coils)	0x01
1	9999	1	Write	Force single Coil (Write Coils)	0x05
1	9999	2 - 512	Read	Read Coil Status (Read Coils)	0x01
1	9999	2 - 512	Write	Force Multiple Coils (Write Coils)	0x15
10001	19999	1 - 512	Read	Read Input Status (Read Digital Inputs)	0x02
30001	39999	1 - 125	Read	Read Analog Inputs (Read IP Registers)	0x04
40001	49999	1 - 125	Read	Read Holding Register (Read Registers)	0x03
40001	49999	1	Write	Preset Single Register (Write Registers)	0x06
40001	49999	2 - 123	Write	Preset Multiple Registers (Write Registers)	0x16

Modbus

address range of the variables as mapped in the

Trusted®

system. Requires only the starting address; automatically calculates the end address.

Address range of variables for the slave. Enter the start and end addresses. See

Message Type

for available address ranges and maximum number of addresses in a single message.

Modbus

address of an application variable used to control the message. Where a control variable is defined for either a broadcast or slave message, the message is enabled when the coil or holding register contains a zero value. These are the valid values for a message control coil or holding register. All other values disable the message. The data type used for control variable can be either Boolean (coil) or integer (holding register).

Use different

Modbus

addresses for all control and status holding registers, and control variable coils.

Variable Data Type	Value	Message
Boolean (coil)	False	Enabled
	True	Disabled
Integer (holding register)	0	Enabled
	Non-zero	Disabled