3 Modbus protocol description
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3.9.2 Error messages for invalid values
For measured values in the floating-point format, the error is displayed in the value itself, i.e. it contains
the error code instead of the measured value.
Example
Read measured value of analog input (from word address 0x7000):
The error code 0x7DB48E52 (= 3.0 × 10
37
) means that this is an invalid input value.
Error code for floating-point val-
ues
Error
1.0 × 10
37
Measuring range underflow
2.0 × 10
37
Measuring range overflow
3.0 × 10
37
Value invalid
4.0 × 10
37
Division by zero
5.0 × 10
37
Math error
6.0 × 10
37
Error: terminal temperature/compensation signal
7.0 × 10
37
Probe short circuit
8.0 × 10
37
Probe break
Data request:
01 03 70 00 00 02 DE CB
Slave Function Word address Number of words CRC
Response:
01 03 04 8E 52 7D B4 51 ED
Slave Function Bytes read Error code CRC