4. FUNCTIONS
MELSEC-A
4-15
4.5.3
Remote OD
In the PROFIBUS the client reads the server local OD using the GetOD service and maintains this
information in the local station to be used while communicating. This maintained information is called
the remote OD.
(1) AJ71PB96F/A1SJ71PB96F
remote
OD
management
The remote ODs managed by the AJ71PB96F/A1SJ71PB96F are divided into two types:
Automatic management remote OD (hereafter automatic remote OD) and preload remote OD.
In the AJ71PB96F/A1SJ71PB96F the remote OD is managed for each communication and a
maximum of 26 remote ODs can be managed for one communication. However, this number is
the total of the automatic remote ODs and preload remote ODs, and a maximum of 20 preload
remote ODs can be set for one station. Preload remote ODs are set using the software package.
Automatic remote ODs use vacant space in the preload remote ODs.
(a) Automatic
remote
OD
When the AJ71PB96F/A1SJ71PB96F issues a Read/Write service, if the specified variable
remote OD is not stored in the AJ71PB96F/A1SJ71PB96F, the AJ71PB96F/A1SJ71PB96F
automatically issues a GetOD to acquire the variable remote OD and this acquired remote
OD is stored in the AJ71PB96F/A1SJ71PB96F.
Yes
No
Yes
No
Yes
No
GetOD
GetOD
GetOD
Read/Write
Read/Write
Read/Write
AJ71PB96F
A1SJ71PB96F
Parther station
ACPU
Request
End
OD header search
Yes
Yes
Yes
OD header
acquisition
OD header
storage
Variable OD search
Variable OD
acquisition
Variable OD
storage
Data type search
Data type
acquisition
Data type
storage
Read/Write issued