Endress+Hauser EngyVolt RV15, Руководство по эксплуатации

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EngyVolt RV15 Appendix
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Data must be written in register pairs i.e. the “Starting Address“ and the “Number of Points”
must be even numbers to write a floating point variable. If the “Starting Address” or the
“Number of points” is odd then the query will fall in the middle of a floating point variable the
product will return an error message.
In general only one floating point value can be written per query.
The following response indicates that the write has been successful. But see also “Exception
Response” later.
Field name Example (Hex)
Slave address 01
Function 10
Starting address High 00
Starting address Low 00
Number of registers High 00
Number of registers Low 02
Error check Low 41
Error check High C8
11.4.10 Exception response
If the slave in the “Write Holding Register” example above, did not support that function then it
would have replied with an Exception Response as shown below. The exception function code is
the original function code from the query with the MSB set i.e. it has had 80 hex logically OR'ed
with it. The exception code indicates the reason for the exception. The slave will not respond at all
if there is an error with the parity or CRC of the query. However, if the slave can not process the
query then it will respond with an exception. In this case a code 01, the requested function is not
support by this slave.
Field name Example (Hex)
Slave address 01
Function 10 OR 80 = 90
Exception code 01
Error check Low 8D
Error check High C0
11.4.11 Exception codes
Table of exception codes
Exception code Modbus protocol name Description
01 Illegal function The function code is not supported by the product.
02 Illegal data address Attempt to access an invalid address or an attempt to read or
write part of a floating point value.
03 Illegal data value Attempt to set a floating point variable to an invalid value.
05 Slave device failure An error occurred when the instrument attempted to store
an update to its configuration.