5-8
IM 77C01H01-10EN
Responses to Abnormal Messages
If there is any failure other than transmission errors, the UPM100 returns the following
response message without executing any process:
Element
Start of
Message
Mark (:)
Station
Number
(ST-NO)
Function
Code (*1)
Error
Code
Error
Check
[CR][LF]
Number of bytes in RTU mode
None
1
1
1
2
None
Number of bytes in ASCII mode
1
2
2
2
2
2
*1: The value of “Function code (Hex) + 80 (Hex)” for the Function code.
The following table summarizes details on the error codes.
Error Code
Meaning
Cause
01
Function code error
Function code does not exist.
02
Abnormal D register number
D register number out of the range is specified.
03
Abnormal number of D registers
Number of D registers out of the range is specified.
The UPM100 does not regard it as an error even if there is any unused register among
those with consecutive register numbers specified by a readout function; rather, the UPM100
returns a value of 0 in this case.
The UPM100 returns the error code 02 or 03 if the specified consecutive registers are
made to fall outside the given range by the number of registers specified, even though the
D-register start number was initially within the range. (Depend on the function code.)
Cases when There Are No Responses to Transmitted Messages
• A transmission error (overrun, framing, parity, LRC or CRC-16 error) is encountered.
• The station number in the command message is wrong.
• The interval between data composing a message is longer than 2 seconds.
• The station number is “00” (broadcast specification).
• The receiving buffer has overflowed.
Note: As a measure against the abovementioned problems, add a time-out process to the
communication function or program of the higher-level device.
5.1 Overview
Summary of Contents for UPM100
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