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Change format of AnalogInput get an error "An attempt has been made to write a property defined as inaccessible through the BACnet protocol write services"


When open a BACnet AnalogInput  from BACnet device side, the value of the object display as 3 decimal digits, The format can be changed by fill the format field as desired, when click the "apply " button, an error prompt box pop out, "An attempt has been made to write a property defined as inaccessible through the BACnet  protocol write services", click the "Apply" button again, the error disappeared and the format has been changed successfully.






Format is not a standard BACnet property, it is Continuum attributes, when change the format, the Cyberstation send a command out to change the "present value" of the point, obviously, it is a defect, on the other hand the present value of AnalogInput  can  not be written, so the error happens. When click "apply" or "ok" for the second time, cyberstation only write attribute of the point in database , not send a command to controller anymore, so we can get a successful change of format for AnalogInput by click "apply" twice.

For AnalogValue, the "present value" of  AnalogValue can be written, so there is no error when change the format of AnalogValue.


  1. Do not care about the error when do the change, click the "Apply" button twice after fill the field beside "Format"
  2. It is defect, install the hotfix when it be released.
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Last update:
‎2018-09-06 11:08 AM
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