User guide

7-9
M-4662
Specifications
1
2
3
4
5
6
7
App
Index
HoldRegister(sharedwiththeModbusslavefunction)
• Common Items
• The client device can read and write to the hold registers.
• Communication input data is an option (/M1 or /PM1).
• External input channels are an RD-MV2000 option (/MC1).
To Write Data
• Communication input data can be handled on a computation channel by writing an
expression that contains the data in an MV computation channel.
• External input channel data can be handled on an external input channel.
• Details
HoldRegister Data DataType
40001 Communication input data C01 16-bit signed integer
| |
40060 Communication input channel C60
• Precautions to be taken when a client device reads data
The MV communication input data is in floating point format, but the data is converted to
16-bit signed integer when the data is read.
• Precautions to be taken when a client device writes data
A client device can only write data in 16-bit signed integer format. A client device cannot
write a floating point value.
40301 Lower word of communication input data C01 32-bit floating point
40302 Higher word of communication input data C01
| |
40419 Lower word of communication input data C60
40420 Higher word of communication input data C60
• Precautions to be taken when a client device writes data
Input range: –9.9999E29 to –1E–30, 0, 1E–30 to 9.9999E29
If values outside this range are used on a computation channel, a computation error
occurs.
41001
External input channel write register 201 16-bit signed integer
| |
41240
External input channel write register 440
• Precautions to be taken when a client device writes data
A client device can only write 16-bit signed integer data.
The measurement range and unit are set on the external input channels. The decimal
place is determined by the external input channel’s span lower settings.
ModbusErrorResponse(commontoModbusserverandModbusslave)
The MV returns the following error codes to a client or master device.
Code Function Operation
1 Bad function code Unsupported function request.
2 Bad register number Tried to read or write to a register that does not have a
corresponding channel.
3 Bad number of registers When writing: The specified number of registers is less than
or equal to zero or greater than or equal to 124.
When reading: The specified number of registers is less than
or equal to zero or greater than or equal to
126.
The MV does not return a response in the following cases.
• CRC error
• Errors other than those shown above.
7.3 Modbus Protocol Specifications