COMMUNICATION MANUAL
GXE600 SERIES
TDKLambda
<Page>
10/79
2) Response frame
The response message frame of MODBUS-RTU consists of the following fields.
The structure of each field is the same as the query frame, but the value of the ID field is limited to the individual
slave ID (1 - 247).
3) Exception response frame
The exception response message frame of MODBUS-RTU consists of the following fields.
The configuration is the same as the query frame except for the following fields.
・FC (Function Code) : For the exception response, use the query FC + 0x80
Example) Exception response FC to query FC 0x10 ⇒ 0x90
・Exception Code : 1 byte code indicating the content of the exception
In the case of GXE, the following exception code may be returned.
Code
Name
Contents
0x01
ILLEGAL FUNCTION
Unsupported function code
0x02
ILLEGAL DATA ADDRESS
Undefined register address (including reserved address)
0x03
ILLEGAL DATA VALUE
Invalid data
0x04
SLAVE DEVICE FAILURE
Slave device error
SLAVE DEVICE BUSY
Slave device busy
3.2.3 Operation in sleep mode
GXE has a sleep mode and contributes to reduction of standby power, but communication function cannot be used
during sleep mode. In sleep mode, GXE will resume normal operation by the signal on RS-485 as a trigger.
At this time, the content of the signal does not matter, but GXE cannot receive the contents of the signal, so that
the response will not be returned. Send the query again from the master device after the wake up time as shown
in the example below.
0x06
SFD
ID
FC
D0
D1
…
Dn-1
Dn
EFD
T3.5>
…
LSB
MSB T3.5>
ADU : serial line Appication Data Unit
PDU : Protcol Data Unit
CRC16
SFD
ID
FC
EFD
T3.5>
LSB
MSB T3.5>
PDU
Exception Code
CRC16
ADU
