Yokogawa Data Acquisition with PID Control CX2000 - Manual (Page 117)

5-7
IM 04L31A01-17E
5
Ladder Communication Protocol
Response against a write command
Number of BCD Digits Command Element
2
2
4
1
1
1
1
4
Station number
CPU number (01)
D register number
0
5th digit
1
+/–
dddd
2 CR(0D)
Number of Bytes
1
1
2
1
1
2
1
1
2 LF(0A)
Example
Command for writing data 200 to the 1
st target setpoint (D register 1101) of CX station
number 01
01011101001002000D0A
Response that returns the same data value 200 (BCD code) as a result of a successful
command execution
01011101001002000D0A
Response When Errors Occur
The table below shows the error responses that the PLC receives when errors occur.
Error Status
When a non-existing parameter
number is transmitted
When a parameter other than
the station number is
transmitted using characters
other than BCD code.
When a parameter other than
the station number is transmitted
using the LF code (0A).
When the station number is
different from the device's
station number.
When the number of registers
to be read is outside the 1 to 64
range.
When writing fails
When the command length
is not correct (command length
is 10 bytes including CR and LF).
When a timeout occurs during
transmission (timeout is 5 s).
When the transmission buffer
overflows (buffer overflow is 200
bytes or more).
When a communication framing
error or parity error occurs.
PLC Transmission data
(Command)
0101 0000 0000 0001 0D0A
0000: Wrong parameter number
0101 0123 0000 000B 0D0A
0101 0123 000B 0000 0D0A
0101 0123 0B00 0000 0D0A
0101 012B 0000 0000 0D0A
0101 0123 0000 000A 0D0A
0101 0123 000A 0000 0D0A
0101 0123 0A00 0000 0D0A
0101 010A 0000 0000 0D0A
0103 0123 0000 0000 0D0A
0001 0123 0000 0000 0D0A
3301 0123 0000 0000 0D0A
0101 0125 0000 0068 0D0A
0101 0125 0000 FFFF 0D0A
PLC Reception data
(Response When
an Error Occurs)
0101 FFFF FFFF FFFF 0D0A
0101 0000 0000 FFFF 0D0A
(“FFFF” is returned.)
No response.
No response.
0101 0123 0011 F050 0D0A
FXXX: Error code (where XXX
is the error code number
(see appendix 7)).
No response.
No response.
No response.
No response.
0101 0123 0000 00 0D0A
0101 0123 00 0000 0D0A
0101 0 0000 0000 0D0A
Note
If an attempt is made to read a parameter that does not exist in the D register list, the CX returns
“0” instead of an error.
5.3 Communications with PLCs