Binary Output Status Points And Control Relay Output Blocks - ABB 615 Series Manual

Section 3
Vendor-specific implementation
3.2.2
14
Table 2: Default Class assignment for Binary Input points
Point index Name/description
See the point list manual.

Binary output status points and control relay output blocks

The BOS points (object 10) and the CROBs (object 12) are provided in the
configuration-specific point list.
While BOS points are included here for completeness, that is they are required by the
DNP 3.0 standard, they are not often polled by DNP 3.0 Masters. The DNP 3.0
standard recommend that BOS points represent the most recent DNP 3.0 commanded
value for the corresponding CROB point. Because many, if not most, CROB points
are controlled internally through pulse mechanisms, the value of the output status
may be meaningless.
As an alternative, the actual status values of CROB points have been looped around
and mapped as BIs and in the case of the breaker, as AI. BOS points that relate to
physical binary outputs are in this implementation looped back and mapped as binary
inputs. The actual status value, as opposed to the commanded status value, is the value
of the actuated control. For example, a DNP 3.0 control command may be blocked
through hardware or software mechanisms; in this case, the actual status value would
indicate the control failed because of the blocking. Looping CROB actual status
values as BIs has several advantages:
• it allows actual statuses to be included in class 0 polls,
• it allows change event reporting of the actual statuses, which is a more efficient
and time-accurate method of communicating control values,
• and it allows reporting of time-based information associated with controls,
including any delays before controls are actuated, and any durations if the
controls are pulsed.
BOS points that relate to some kind of software binary output points, that is reset- or
acknowledge points, are not looped back as binary inputs.
The default select/control buffer size is large enough to hold 10 of the largest select
requests possible.
DNP 3.0 pulse commands, and associated count, off-time and on-time, are not
supported in this implementation.
From the IED's perspective, there are two types of CROB points. Most are internally
mapped to IEC 61850 SPC, while the breaker control is mapped to 61850 DPC.
SPC based CROB, for example, physical outputs and LEDs:
1MRS756709 A
Default change event assigned class (1, 2, 3
or none)
1
Communication Protocol Manual
615 series