Omron CJ - REFERENCE MANUAL 07-2009

93
Communications Frames Section 3-7
• Modbus-RTU Settings
Command Frame
Response Frame
[CMND S D C]
Command Details
Item Set value Setting location
FINS command code: Converting to
Modbus-RTU = 2804 hex
2804 hex Set 2804 hex in controller data
s of the CMND(490) instruc-
tion.
Modbus slave address (e.g., 02 hex) 02 hex Set 0210 hex in controller data
s+1 of the CMND(490) instruc-
tion.
FUNCTION code: DATA WRITE = 10
hex
10 hex
Write data register No. (e.g., frequency
reference = 0002 hex)
0002 hex Set 0002 hex in controller data
s+2 of CMND(490).
Number of write data registers (e.g, 1
register)
0001 hex Set 0001 hex in controller data
s+3 of CMND(490).
Number of attached data registers
Note: Set 02 hex of this value in the
leftmost byte of S+4. Set 00 hex as the
leftmost register No. in the rightmost
byte of S+4.
0200 hex Set 0200 hex in controller data
s+4 of CMND(490).
Register No. 0002 hex data (e.g., 0064
hex)
Note: Set 64 hex as the rightmost regis-
ter No. in the leftmost byte of S+5.
6400 hex Set 6400 hex in controller data
s+5 of CMND(490).
Item Setting Setting location
Modbus Slave address (e.g., 02 hex) 02 hex Stored in D+2 of CMND(490)
FUNCTION code: Write data (= 10 hex) 10 hex
Write data register No. (e.g., frequency
reference = 0002 hex)
0002 hex Stored in D+3 of CMND(490)
Write data registers (e.g., 1 register) 0001 hex Stored in D+4 of CMND(490)
Operand Offset Value Meaning
S:
D01000
+0: 2804 hex Conversion to Modbus-RTU (FINS command code: 2804 hex)
+1: 0210 hex Modbus-RTU slave address: 02 hex, FUNCTION code: 10 hex (DATA WRITE)
+2: 0002 hex Write data register No.: 0002 hex (frequency reference)
+3: 0001 hex Number of write data registers: 0001 hex (1 register)
+4: 0200 hex Number of attached data bytes: 02 hex (2 bytes); Leftmost register No.: 00 hex
+5: 6400 hex Rightmost register No.: 64 hex (Frequency reference value: 10.0 Hz when unit is 0.1
Hz), blank = 00 hex
D:
D02000
First response storage word
C:
D00000
+0: 00 0C hex Number of command data bytes: 000C hex (12 bytes decimal)
+1: 00 0A hex Number of response data bytes: 000A hex (10 bytes decimal)
+2: 0002 hex Send destination network address: 02 hex; Serial port number: 0 hex (direct serial port
unit address specification)
+3: 058C hex Send destination node address: 05 hex; Send destination unit address: 8C hex
+4: 0000 hex Response required; Communications port number: 0; Resends: 0 hex
+5: 0000 hex Response monitoring time: 2 s