When opening a BACnet AnalogInput from (the Blue) BACnet device side, the value of the object displays as 3 decimal digits by default. The format can be changed in the format field as desired, however when clicking the "Apply" button, an error prompt box pops up with the message "An attempt has been made to write a property defined as inaccessible through the BACnet protocol write services". if the "Apply" buttonis clicked again, the error disappears and the format is been changed successfully.
- Continuum BACnet
- V2.02 and earlier.
Format is not a standard BACnet property, it is a Continuum attribute and when the format is changed Cyberstation sends a command to change the "present value" of the point in the controller. The present value of AnalogInput cannot be written so the error occurs. When clicking "apply" or "OK" for the second time Cyberstation only writes the attribute of the point in the database rather than the controller. Therefore we can get a successful change of format for AnalogInput by clicking "Apply" twice.
For AnalogValue, the "present value" of AnalogValue can be written in BACnet, so there is no error when changing the format of an AnalogValue.
Ignore the error when making the change, click the "Apply" button twice after updating the "Format".
Or upgrade to V2.03 where this issue has been resolved.