ABB 620 Series Manual page 19

1MAC459571-IB C
620 series ANSI
Communication Protocol Manual
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 command status value, is the value of the actuated
control. For example, a DNP3 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.
DNP3 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:
• Operation is blocked unless the IED is in the remote switch position.
• Timeout selection is configurable.
• SPC points support both DIRECT (Direct Operate) and SBO (Select-Before-
Operate).
LED output points only support latch off and trip commands. An error will
be returned by the IED if latch on or close is sent to an LED output.
DPC based CROB, for example, breaker control:
• Operation is blocked unless IED is in the remote switch position.
• Timeout selection is configurable.
• DPC point DIRECT/SBO behavior is determined by the Control_model parameter in
Configuration/Control/52(2)/Control_model.
Vendor-specific implementation
Section 3
13