YASKAWA CIPR-GA50C series Technical Manual page 214

6.3 MEMOBUS/Modbus Communications
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Loopback Test
The loopback test uses function code 08 (Hex.) and returns the command message as a response message. This
test checks communication between the master and slave. The test code and data can use desired values.
Figure 6.10 shows examples of messages given out when the loopback test is done with the drive of slave 1.
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Writing to Multiple Holding Registers
You can write the data that you set to the number of holding registers set in function code 10 (hex). You must
configure the number of the holding registers and each 8 higher bits and 8 lower bits in order in the command
message for the write data. You can write to a maximum of 16 holding registers.
Figure 6.11 shows example messages when you use the PLC to set Forward run in the drive of slave 1 with a
60.00 Hz frequency reference.
When you rewrite the parameter value with the write command through the H5-11 [Comm ENTER Command
Mode] setting, you must use the Enter command to save and enable the contents of the changes. Refer to
Comm ENTER Command Mode on page 656
Figure 6.11 Message Example When Writing to Multiple Holding Registers
Note:
The number of bytes set in the command message set the data quantity × 2 during the command message. The response message uses
the same formula.
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Reading from More than One Holding Register/Reading the Indicated Register
The drive uses function code 5A (Hex.) to write to more than one register, then it reads the contents of four
holding registers at the same time.
The function for writing to more than one register is the same as the function for function code 10 (Hex.). You can
write to a maximum of 16 holding registers.
The four holding registers to be read from are specified in H5-25 to H5-28 [Function 5A Register x Selection].
Table 6.6 shows example messages when you write to more than one holding register or when you read more than
one command register. Table 6.6
• The drive for slave 1 is set for Forward run with a frequency reference of 60.00 Hz.
214
Figure 6.10 Message Example When Doing the Loopback Test
and Enter Command on page 217
uses this register data for the examples:
for more information.
YASKAWA SIEPC71061753A GA500 Technical Manual
H5-11: