ELC500 Control unit
175
System Relays (SR)
9.6
ELC500 uses the following system relays (SR).
These system relays can be used in programs.
Device No.
Name
Description
SR0
Self-diagnostic error flag
Turns on when a self-diagnosis error occurs. Self-diagnosis error codes are
saved in the system data register SD0.
SR1
Unit alarm occurrence
Turns on when a unit alarm is detected. The slot number of the unit where
an alarm has occurred is saved in the system data register SD1.
SR2
Unit error occurrence
Turns on when a unit error is detected. The slot number of the unit where an
error has occurred is saved in the system data register SD2.
SR3
Unit warning occurrence
Turns on when a unit warning is detected. The slot number of the unit where
a warning has occurred is saved in the system data register SD3.
SR4
Unit verification error
occurrence
Turns on when an I/O verification error is detected. The slot number of the
unit where an I/O verification error has occurred is saved in the system data
register SD4.
SR5
Unit installation error
detection
Turns on when a unit installation error is detected. The slot number of the
unit where an I/O verification error has occurred is saved in the system data
register SD5.
SR7
Operation error flag
(hold type)
Turns on when an operation error occurs after the unit has started
operating, and remains on while the unit operation continues. The PB
number where an error has occurred is saved in the system data SD7, and
the address is saved in system data registers SD8 to SD9. It indicates the
first operation error that has occurred.
SR8
Operation error flag
(latest type)
Turns on every time an operation error occurs. The PB number where an
operation error has occurred is saved in the system data register SD10, and
the address is saved in system data registers SD11 to SD12. Every time a
new error occurs, the data are updated. It does not turn off even if the
instruction is normally completed after the occurrence of the error(s). In
order to check if any error has occurred in a specific instruction, either see
address data saved in the SD, or clear error flags using ERR instruction
immediately before the specific instruction, and check flags immediately
after executing the instruction.
SR9
Carry flag (CY flag)
Used in shift instruction and rotate instruction with a carry flag. The flag can
also be operated in carry set instruction and carry reset instruction. It is not
set in overflow or underflow of operation results.
Turns on when an error occurs during the execution of Ethernet
communication instruction. The error code is stored in the system data
register SD29.
SRA
> flag
Executes comparison instruction, and turns on if the result is larger.
SRB
= flag
Executes comparison instruction, and turns on if the result is equal.
Executes operation instruction, and turns on if the result is '0'.
SRC
< flag
Executes comparison instruction, and turns on if the result is smaller.
SRD
Support timer instruction
flag
Turns on after support timer instruction (SPTM) is executed and
subsequently specified time has passed. Turns off when execution
conditions go off.
SRE
All error alarms relay
Turns on when any of the error alarm relays E0 to E4095 turns on.
Turns off once all of the error alarm relays go off.
SRF
Constant scan error
flag
Turns on if scan time exceeds the setting during constant scan. It
also turns on if '0' is set in FP7 configuration.
