ABB Rellon 620 Series - Overflow Situation Clearing; Supported Data Types; Indications (MSP, MDP); Measurements (MMENA, MMENB, MMENC, MMEND)

Section 3 1MAC306892-MB C
Vendor-specific implementation
16 RER620
Communication Protocol Manual
Knowing that the missed data is not included in the interrogation list, the client can skip
interrogation. If the addresses are configured to same (default), only one indication is sent
regardless if the data is included in the interrogation or not.
3.3.3 Overflow situation clearing
After the event buffer overflow is cleared, the protective relay discards new events for 3
seconds to allow the client to start fetching the events and to free some space in the event
buffer. Otherwise, the event buffer overflows immediately again and the communication
is disturbed more.
3.4 Supported data types
3.4.1 Indications (MSP, MDP)
The protective relay supports both single and double-bit indications with configurable
timestamp format.
3.4.2 Measurements (MMENA, MMENB, MMENC, MMEND)
By default, analog measurements are transmitted in primary units, such as A, V or Hz. The
scaling is based on the measuring transformer ratio.
3.4.3 Control objects (CSC, CDC)
Two types of control objects are available. The double bit controls are employed for circuit
breaker control points. The C_DC_XX (46, 59) type commands should be issued to control
the double bit points.
The single bit controls are used for all the other control points, e.g., setting group selection,
clearing the indication LED's or recorded data and etc. The C_SC_XX (45, 58) type
commands should be used to control the single bit points.
If the command type and point type do not match, the Negative Confirmation with COT
47 UKIOA_NEGA (Unknown IOA Origin) response will be sent.
Both select-before-operate command and direct operate command can be used for all
control points regardless the configuration of the SCBXCR control mode.
A command is rejected because of:
• Control direction is wrong.
• Legal values for double-bit controls are 1 and 2. Both 0 and 3 are rejected.
• Control object is set to "Status-only".
Overflow situation clearing is applicable only for the keep oldest events
mode.