Mitsubishi Electric MELSEC iQ-R - Page 35

1 FUNCTIONS
1.1 BACnet Object Function
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Settings using a program
The property values in a BACnet module can be changed by writing values to the buffer memory using a program.
■ Settings at normal operation
1. Write the CONTROL whose OutOfService and Reliability are '0'. (No writing is required when '0' has already been
written.)
■ To change an OutOfService property to True
1. Write the CONTROL whose OutOfService is '1' to the buffer memory.
Precautions
• When the OutOfService is '1', the PresentValue and the Reliability are not used.
• Leave the OutOfService of the CONTROL '1' until the OutOfService of the StatusFlags becomes '1' (1 second or more).
■ To change an OutOfService property from True to False
1. Write a value to the PresentValue.
2. Write the CONTROL whose OutOfService value is '0' and Reliability value is an appropriate one.
Precautions
• When the Reliability is other than '0', writing a value to the PresentValue is unnecessary.
• Leave the OutOfService of the CONTROL '0' until the OutOfService of the StatusFlags becomes '0' (1 second or more).
■ Settings for a Reliability property at error occurrence
1. Write the CONTROL whose OutOfService is '0' and Reliability is other than '0'.
■ Detection of writing by a WriteProperty service
After a value is written to a PresentValue property in the internal memory with a WriteProperty(Multiple) service, a BACnet
module writes '1' to the PVWritten of a STATUS.
By using a PVWritten as a flag in a program, a write to the PresentValue property in a BACnet module can be detected. Apply
the value of the PresentValue property to the program while the PVWritten is '1'.
To restore the PVWritten to '0', use the PVWrittenClear of a CONTROL as follows.
1. Set '1' to the PVWrittenClear of the CONTROL in the buffer memory.
2. Wait until the PVWritten of the STATUS in the buffer memory becomes '0'.
3. Set '0' to the PVWrittenClear of the CONTROL in the buffer memory.