Date Code 20010518 General Description 2-5
SEL-2020 Instruction Manual
These capabilities offer substantial advantages. Fast Meter data received from SEL relays
consist of raw voltage and current samples. In many cases, the SEL-2020 calculates more output
quantities from the raw data than the SEL relay that sampled the original data; these additional
output quantities include current and voltage phasor angles, per-phase megawatts and megavars,
and complete sequence components.
Fast Meter binary data are collected at a much higher speed than ASCII formatted data. Binary
data transfer is not interrupted during transparent port communications, nor is it interrupted by
ASCII data collection; ASCII data transfer is interrupted by transparent port communication. We
highly recommend using relays with Fast Meter capability with the SEL-2020.
Non-“20” messages. Non-“20” responses can be ignored, or parsed using any one of five pars-
ing options: ASCII Integer, ASCII Floating point, Character string, Integer string, and Integer
string with XON/XOFF encoding. Non-“20” messages are primarily for use with devices other
than SEL relays (see Section 8: Message Strings for more information).
You can use the SET A command to create SEL
OGIC Control Equations for message triggering
and the associated message strings. Also use SET A to set the AUTOBUF switch that
determines if unsolicited messages will be stored or ignored. (See Section 6: Settings.)
SELOGIC CONTROL EQUATIONS PROGRAMMABLE CONTROLLER
You can trigger messages and control action with SELOGIC Control Equations.
The SEL-2020 issues messages when a user-defined condition for issuing the message is true.
The condition is defined for each message by a SEL
OGIC Control Equation using:
• Time (Thh:mm:ss.s)
• Period (Phh:mm:ss.s with optional start and stop time)
• Internal trigger using any bit in the SEL-2020 Database, including:
− Global elements: Day-of-week, intermediate logic elements (V, W, X, Y, Z, XT, YT,
and ZT), remote bits, and external inputs (from optional I/O board)
− Local elements: User-defined command elements, select-before-operate elements,
database triggers, and relay operate elements
− Relay elements: from SEL TARGET data
or any logical combination of the above.
SEL
OGIC Control Equations use OR (+), AND (*) and NOT(!) operations to combine terms. The
SEL-2020 Global region includes intermediate variables V, W, X, Y, and Z, to provide additional
SEL
OGIC Control Equation message capability. Intermediate variables X, Y, and Z have
associated timers to provide even greater control capability and flexibility. (See Section 7:
SEL
OGIC Control Equations.)
Twelve message groups are available per port. Messages 1 to 8 have associated data buffers to
store responses. Four message groups, Messages 9 to 12, are for messages only, having no asso-
ciated data buffer.
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