Input Words Control Modes
Original instructions
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Purpose
This section describes input words control modes.
Input Words 3 ... 4
NOTE: In control mode 0, input words 3 and 4 are zeroed.
NOTE: The message response code is contained in the Modbus message itself, so control mode 1, input buffer words 3 ... 16 are used as the actual message.
NOTE: For control modes 2 ... 8, all four response fields are present whether used or not. The table below shows the input message responses to words 3 and 4.
Control Modes 2 ... 8
Input Word 3 High Byte
Input Word 3 Low Byte
Message 1 response
Message 2 response
Input Word 4 High Byte
Input Word 4 Low Byte
Message 3 response
Message 4 response
Input Words 5 ... 16
Input words 5 ... 16 contain Modbus message response data.
NOTE: Refer to General Modbus Message Rules.
Input Words Mode Memory Allocation
The tables below describe the specific memory allocation for each control mode.
Control Mode 0
Control Mode 0 - Idle, Clear Response Buffer
Word 1
Sequence #
Word 2
Status
6 120Vac inputs
Word 3 ... 16
Message data field = (00) hex
Control Mode 1
Control Mode 1 - Modbus Message
Word 1
Sequence #
Word 2
Status
6 120Vac inputs
Word 3 ... 16
Modbus Message data response
Control Mode 2 and 4
Control Mode 2 and 4 - Write Commands
Word 1
Sequence #
Word 2
Status
6 120Vac inputs
Word 3
Message 1 response
Message 2 response
Word 4
Message 3 response
Message 4 response
Word 5 ... 16
Not used. Input data values are 0
Control Mode 3 and 5
Control Mode 3 and 5 - 1 Write Command and 1 Block Read Command
Word 1
Sequence #
Word 2
Status
6 120Vac inputs
Word 3
Message 1 response
Message 2 response
Word 4
Message 3 response
Message 4 response
Word 5 ... 16
12 words of message input data
Control Mode 6
Control Mode 6 - 2 Single Write Commands and 2 Block Read Commands
Word 1
Sequence #
Word 2
Status
6 120Vac inputs
Word 3
Message 1 response
Message 2 response
Word 4
Message 3 response
Message 4 response
Word 5 ... 16
12 words shared between 2 input responses
Control Mode 7
Control Mode 7 - 1 Write Command and 3 Block Read Commands
Word 1
Sequence #
Word 2
Status
6 120Vac inputs
Word 3
Message 1 response
Message 2 response
Word 4
Message 3 response
Message 4 response
Word 5 ... 16
12 words shared between 3 input responses
Control Mode 8
Control Mode 8 - 4 Block Read Commands
Word 1
Sequence #
Word 2
Status
6 120Vac inputs
Word 3
Message 1 response
Message 2 response
Word 4
Message 3 response
Message 4 response
Word 5 ... 16
12 words shared between 4 input responses