Yokogawa Standalone MW100 - Manual (Page 234)

5-21 IM MW100-01E
Specification
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App
Index
Modbus Protocol Specifications
Common to Modbus Master Function and Modbus Slave Function
Communication possible in RTU mode of the Modbus protocol
Communication media: RS-232, RS-422A/485
Control method:
No flow control (None only)
Baud rate: Select 1200, 2400, 4800, 9600, 19200, 38400, 57600, or 115200
bps
Start bit: 1 bit, fixed
Data length: 8 bit, fixed
Parity: Select Odd, Even, or None
Stop bit: Select either 1 or 2 bits
Transmission mode: RTU (remote terminal unit) mode only
Slave address:
1 to 247 (slave address only)
Modbus Master Function (/M1 option)
Communication interval: The interval for reading and writing data to and from other
instruments is selected from the following.
100, 200, 250, 500 ms, or 1, 2, 5, 10, 20, 30, 40, 50, 60, 90,
120 s
Depending on the performance of the main unit, if data reading
and writing is not possible at the set communication interval,
data loss results. If this occurs, the previous value is held for
the communication input channel data. In this case, you must
lengthen the communication interval, or reduce the load on the
main unit.
Timeout time: From the following, select a timeout time for no response from
the specified slave after sending commands from the main unit.
100, 200, 250, 500 ms, or 1 s
Number of retries: The number of transmissions attempted if no response to
commands from the main unit are received from the slaves.
Select from the following: OFF, 1, 2, 3, 4, or 5
Communication recovery time: You can select from the following the send interval for the
command sent after the point at which there is no
response from the slaves after sending commands the
specified number of retry times.
1 to 120 s
Wait between commands: Select a time to wait between receiving of the response to
a command until the next command is sent.
Off, 0, 10, 20, 50, 100 ms
Supported functions: The functions that the MW100 supports are as follows.
Function Code Function Action
1 * Read statuses of coils (0xxxx) Reads statuses of a series of coils.
2 * Read statuses of input relays (1xxxx) Reads statuses of a series of input
relays.
3 Read values of hold registers (4xxxx,
4xxxxx)
Reads values of a series of hold
registers.
4 Read values of Input registers (3xxxx,
3xxxxx)
Reads values of a series of input
registers.
5 * Turn status of a single coil (0xxxx) Turns off/on a single coil.
6 Write a value to a single hold register
(4xxxx, 4xxxxx)
Writes a value to a hold register.
15 * Turn statuses of coils (0xxxx) Turns off/on a series of coils.
16 Write values to hold registers
(4xxxx ,4xxxxx)
Writes values to a series of hold
registers.
* Firmware version R3.04 or later
5.2 Main Module (MW100-E) Specifications