Toshiba GR200 Series Instruction Manual page 585

Double command blocking (DCB)
3.4.1
For control functions, the operating principle is that priority is given to the first command
received and shall be executed first. In other words, successive commands received do not have
the right to run until the first command received has failed to complete its operation (that is,
the principle of double command blocking (DCB) is established). The principle is significant for
protection and control devices in the sub-station†. Figure 3.4-1 illustrates how each control
function generates a SLD_RPT signal; the aggregation of SLD_RPT signals is performed in the
CMNCTRL1 function. The resultant signal is output at PLC connection point "DCB SND OR".
The resultant signal is returned to the respective control function as feedback.
"From 61850
communication
"stVal" message 2
SPOS function
SPOS01 function
DPOS function
DPSY function
TPOS function
SOFTSW function
Figure 3.4-1 DCB operation in CMNCTRL1 function
†Note: Let us assume that the control function in IED-1 controls CB1, as shown in Figure
3.4-2. IEDs -2 to -10 are forbidden to operate their CBs throughout the period that
IED-1 is in operation. Control functions are also forbidden to operate CB1 when
the automatic sequence controlling function (ASEQ) is in operation. We discuss
the ASEQ function later. (See Chapter
510001 0001011001 DCB RCV OR
Reception of "DCB"
Output of "StSeld"
SPOS01_STD_RPT
SPOS02 function
SPOS02_STD_RPT
SPOS03 function
SPOS03_STD_RPT
SPOS20 function
SPOS20_STD_RPT
Reception of "DCB"
Output of "StSeld"
DPOS01_STD_RPT
DPOS01 function
DPOS72 function
DPOS72_STD_RPT
- 562 -
CMNCTRL1 function
DCB SND OR
(510001 0008001F42)
≥1
Control and monitoring application:
6F2S1914 (0.49)
Command "P2-Control" from the rem
To 61850
communication
"stVal" message 1
To control functions
in its own
GRL200 (Soft 033 & 037)