Mitsubishi Electric MELSEC iQ-R - Chapter 1 Functions; Bacnet Object Function

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1 FUNCTIONS
1.1 BACnet Object Function
1 FUNCTIONS
This chapter shows the details of the functions of a BACnet module.
1.1 BACnet Object Function
This function can be used for using a programmable controller system as a BACnet controller.
By registering objects to a BACnet module, various services can be sent to/received from a BACnet workstation and other
BACnet controllers.
Some of the properties of an object are assigned to the data assignment area in the buffer memory and can be accessed from
a program.
Objects can be registered with a configuration function. (Page 166 Registration of BACnet objects)
The following figure shows how a BACnet workstation reads an analog value on a programmable controller system from the
AnalogInput object (instance number: 0) in a BACnet module.
*1: A programmable controller system communicates as a BACnet controller.
*2: AnalogInput object is an object that reads analog values from a programmable controller to a BACnet workstation.
(1) Connect a personal computer to a BACnet module, and register an AnalogInput object (instance number: 0) with a configuration function.
(2) Some of the properties of the AnalogInput object are assigned to the data assignment area in the buffer memory in the BACnet module.
(3) Read an analog value from an analog input module using a program of a CPU module.
(4) Write the analog value read by the program to the PresentValue property of the AnalogInput object assigned in (2).
(5) The PresentValue property value in the buffer memory of the BACnet module is applied to the PresentValue property in the internal memory.
(6) The BACnet workstation sends a service to read the PresentValue property value of the AnalogInput object in the BACnet module.
RCPU
PresentValue
12345
1234512345
D0
(1)
(3)
(4)
(5)
(6)
(2)
CH1
12345
PresentValue
12345
Buffermemory
BACnet workstation
Analog input
module
BACnet module
Programmable controller system
*1
Configuration function
Personalcomputer
Program
AnalogInput object *2
(Instance number: 0)
Property value
Internal memory
AnalogInput object *2
(Instance number: 0)
Property value