Sel SEL-421 - SEL-311 and SEL-351 Series Users

R.3.36
SEL-421 Relay Reference Manual Date Code 20111215
SELOGIC Control Equation Programming
SEL-311 and SEL-351 Series Users
system. It is unlikely that you will find every possible weakness, but careful
consideration and testing for abnormal conditions will help you avoid a failure
and may reveal deficiencies in the normal operation of your system.
Modify your SEL
OGIC control equations to simulate the process. While you
may be unable to change the state of a discrete input easily, such as IN101,
you can substitute a logical 1 or logical 0 in your logic to simulate the
operation of IN101 and observe the results.
Use the SER capabilities of the relay to monitor and record inputs, internal
calculations, and outputs. For operations that occur very quickly, use the SER
during testing to reconstruct the operation of your logic.
Use the MET PMV or MET AMV commands to display the contents of the
last 16 protection or automation math variables.
SEL-311 and SEL-351 Series Users
You can convert logic that you have used in SEL-311 series relays and
SEL-351 series relays to logic for the SEL-421. In the SEL-311 series relays,
SEL
OGIC control equation programming is restricted to equations where the
left side value, LVALUE, is fixed. The SEL-421 uses primarily free-form
programming. Table 3.28 shows comparable features between the SEL-311
series relays and the SEL-421. Convert programming into either the free-form
style or the fixed style of SEL
OGIC control equations, or whatever
combination you deem appropriate for your application.
Tab le 3.29 shows the SEL-421 Boolean operators compared to the operators
used in the SEL-311 series relays.
Table 3.28 SEL-311 Series Relays and SEL-421 SELOGIC Control Equation
Programming Features
Feature SEL-311 Series
SEL-421 Protection
Free-Form Style
SELOGIC control equation variables SV1–SV16 PSV01–PSV64
Timer Input SV1–SV16 PCT01–PCT32
Timer Pickup settings SV1PU–SV16PU PCT01PU–PCT32PU
Timer Dropout settings SV1DO–SV16DO PCT01DO–PCT32DO
Timer Outputs SV1T–SV16T PCT01Q–PCT32Q
Latch Bit Set Control SET1–SET16 PLT01S–PLT16S
Latch Bit Reset Control RST1–RST16 PLT01R–PLT16R
Latch Bit LT1–LT16 PLT01–PLT16
Table 3.29 SEL-311 Series Relays and SEL-421 SEL
OGIC Control Equation
Boolean Operators
Feature SEL-311 Series SEL-421
Logical AND operator * AND
Logical OR operator + OR
Logical NOT operator ! NOT
Parentheses ( ) ( )
Rising, falling edge operators /, \ R_TRIG, F_TRIG