Modbus Message Framing; List Of Implemented Modbus Commands; Ethernet Communication Settings; Time Out For The Lan - Foundation Logic View Configuration Manual

Modbus Message Framing

Interval of start of message

List of Implemented Modbus Commands

Function
Number
1/01H
2/02H
3/03H
4/04H
5/05H
15/0FH
16/10H
17/11H
22/16H
23/17H

Ethernet Communication Settings

The Modbus RTU protocol has a frame basically starting with an interval of silence followed by an
address, function, data, and CRC checking (Cyclic Redundant Checking). Another interval of silence
to indicate the end of the message
Address
Frame size: 255 bytes
In the Modbus RTU standard data is transmitted in bytes with hexadecimal information from 0-9, A-
F. Each byte is sent in the following format:
1 Start Bit
8 Data bits, least significant sent first.
1 Bit for parity (odd or even, if there is parity)
1 Stop bit
Start Bit Data (8 bits)
Function
Name
Read Coil Reads the ON/OFF status of discrete outputs (0xxxx - references, coils)
Status in the slave
Read Input Reads the ON/OFF status of discrete inputs (1xxxx - references) in the
Status slave
Read Holding Reads the binary contents of holding registers (4xxxx references) in the
Registers slave
Read Input Reads the binary contents of input registers (3xxxx references) in the
Registers slave
Force Single
Forces a single coil (0xxxx reference) to either ON or OFF
Coil
Preset Single
6/6H Presets a Value into a single holding register (4xxxx reference)
Coil
Force Multiple
Forces each coil (0X ref.) in a sequence of coils to either ON or OFF
Coils
Preset Multiple
Presets values into a sequence of holding registers (4xxxx references)
Regs
Report Slave
Return a description of the type of controller present at the slave address,
ID (the DF65
the current status of the slave Run indicator, and other information
ID do DF65 is
specific to the slave device
2)
Mask Write
Used to set or clear individual bits in the a 4xxxx register
4xxxx Register
Performs a combination of one read and one write operation in a single
Read/Write Modbus transaction. The function can write new contents to a group of
4xxxx Register 4xxxx register, and then return the contents of another group of 4xxxx
registers
* Only Implemented in firmware versions 1.30xx or higher
** Only Implemented in firmware versions 2.31.03 or higher

Time out for the LAN

For the Ethernet connection the time out will be very dependent on the execution cycle for the DF65
and the traffic in the network. It is a good hint to begin with 5000 ms and 3 communications retries
before error notification.
Go to menu: Tools/Comm. Settings then click on Time out tab.
Function Data CRC check
Parity
Description
Interval of end of message
Stop bit
LogicView
Implementation
OK
OK
OK
OK
OK
OK
**OK
*OK
OK
*OK
OK
3.57