Appendix
A
Appendix
D
Special
R
elays
D--2
Special Relays
DL105 PLC User Manual, 3rd Edition
DL105 PLC Special Relays
“Special Relays” are just contacts that are set by the CPU operating system to
indicate a particular system event has occurred. These contacts are available for
use in your ladder program. Knowing just the right special relay contact to use for a
particular situation can save lot of programming time. Since the CPU operating
system sets and clears special relay contacts, the ladder program only has to use
them as inputs in ladder logic.
SP0
First scan
on for the first scan after a power cycle or program to run transition
only. The relay is reset to off on the second scan. It is useful where a
function needs to be performed only on program startup.
SP1
Always ON
provides a contact to insure an instruction is executed every scan.
SP3
1 minute clock
on for 30 seconds and off for 30 seconds.
SP4
1 second clock
on for 0.5 second and off for 0.5 second.
SP5
100 ms clock
on for 50 ms. and off for 50 ms.
SP6
50 ms clock
on for 25 ms. and off for 25 ms.
SP7
Alternate scan
on every other scan.
SP12
Terminal
run mode
on when the CPU is in the run mode.
SP16
Terminal
program mode
on when the CPU is in the program mode.
SP20
Forced
stop mode
on when the STOP instruction is executed.
SP22
Interrupt enabled on when interrupts have been enabled using the ENI instruction.
SP40
Critical error
on when a critical error such as I/O communication loss has
occurred.
SP41
Warning
on when a non critical error such as a low battery has occurred.
SP44
Program
memory error
on when a memory error such as a memory parity error has
occurred.
SP50
Fault instruction
on when a Fault Instruction is executed.
SP51
Watch Dog
timeout
on if the CPU Watch Dog timer times out.
SP52
Grammatical
error
on if a grammatical error has occurred either while the CPU is
running or if the syntax check is run. V7755 will hold the exact error
code.
SP53
Solve logic error
on if CPU cannot solve the logic.
Startup and
Real-Time Relays
CPU Status Relays
System Monitoring
Summary of Contents for DL105
Page 2: ...DL105 PLC User Manual Manual Number D1 USER M...
Page 308: ...1B DL105 Error Codes In This Appendix Error Code Table...
Page 314: ...1C Instruction Execution Times In This Appendix Introduction Instruction Execution Times...
Page 324: ...1D Special Relays In This Appendix DL105 PLC Special Relays...
Page 327: ...1E PLC Memory In This Appendix DL105 PLC Memory...
