Toshiba GR-200 Series Instruction Manual page 379

Control mode
Either Select-Before-operation (SBO) or Direct-Operate-control (DIR) is provided as a control
mode for the device. The user can select the preferred control mode.
Select-before-operation mode (SBO)
3.2.1
The user should be aware that in the SBO mode a signal is returned from the target device in
the form of a response signal, (answer). When the target device sends a response to the IED
after receiving a command, the server (and the IED) can send another command to the target
device if the criterion of the response (answer) is satisfied. A safe SBO operation (SBOns) is
normally utilized; however, the user can opt to select an enhanced-security SBO operation
(SBOes), if additional safety is deemed necessary.
SBO with enhanced security (SBOes)
(i)
In the SBOes, an operation process (Oper) commences after the completion of a selection
process (SBOw). Figure 3.2-1 exemplifies the exchange of commands and responses; the server
receives a response (answer#1) from the IED with regard to a SBOw command. Then, provided
that the response, (answer#1) received from the IED is satisfied, the server can send an Oper
request to the IED to control the device. If the target device completes the operation
successfully, the server will receive an operation result. Figure 3.2-1 shows the communication
flow between the server (remote-end) and the IED, note that the user will also see the same
process flow when using the IED-front-panel key-operations. That is, the IED-front-panel
(local-end) takes the place of the server (remote-end).
Server
Process
Selection
Operation
R esult
SBO with normal security (SBOns)
(ii)
Figure 3.2-2 shows normal SBOns control. The difference between the SBOes and the SBOns
is that the IED does not send an operation result in response to the request Oper.
IE D
(SAS) (Control function)
SBOw
Answer#1
Oper.
Answer#2
Operation result
Figure 3.2-1 SBO with enhanced security
- 360 -
Target device
Command
R esponse
Command
R esponse
Device status changed
Command
termination
6F2T0200 (0.15)
GRE200 (1,2)