Yokogawa Data Acquisition with PID Control CX2000 - Manual (Page 101)

4-7
IM 04L31A01-17E
4
Modbus Protocol
• UINT32_B
Specify this type when a “32-bit unsigned integer” is assigned to the Modbus
register in the order upper 16 bits followed by the lower 16 bits.
Specify the smaller register number (the higher register number in this case) in
[Registers].
• UINT32_L
Specify this type when a “32-bit unsigned integer” is assigned to the Modbus
register in the order lower 16 bits followed by the upper 16 bits.
Specify the smaller register number (the lower register number in this case) in
[Registers].
• FLOAT_B
Specify this type when a “32-bit floating-point data” is assigned to the Modbus
register in the order upper 16 bits followed by the lower 16 bits.
Specify the smaller register number (the higher register number in this case) in
[Registers].
• FLOAT_L
Specify this type when a “32-bit floating-point data” is assigned to the Modbus
register in the order lower 16 bits followed by the upper 16 bits.
Specify the smaller register number (the lower register number in this case) in
[Registers].
Example (Read multiple points of data using a single command)
If you enter the following settings, the values of register 30001 and register 30002 (both
INT16 type) are read into C01 and C02, respectively.
Displaying the Read Data
The data that is read can be specified by writing a computing equation using C01
through C30 on a computation channel (/M1 option). The decimal point position and the
unit of the register data depend on the slave device. Correct the data that is read using
a computing equation on the CX (see the example below). For information on how to
use the computation channel, see the user’s manual IM 04L31A01-01E or IM
04L31A01-03E
.
Example (Assign communication input data C01 to computation channel 31)
When reading the INT16 data of register 30001 of a slave device at address 1 as
communication input data C01, setting two digits to the right of the decimal point
(multiplying by 0.01), and setting the unit to “V”
• Setting the command
First: 01, Last: 01, Address: 1, Registers: 30001, Type: INT16
• Setting the computation channel
Computing equation of CH31: C01*K01
Unit of CH31: V
Constant: K01=0.01
4.3 Setting the Modbus Master Function