231
Manipulating Files Section 5-2
Operations Continuing
during and after Program
Replacement
When the IOM Hold Bit (A50012) is ON, the data in the following memory
areas will be maintained: the CIO Area, Work Area (W), Timer Completion
Flags (T), Index Registers (IR), Data Registers (DR), and the current EM bank
number.
Note Timer PVs will be cleared during program replacement.
If the IOM Hold Bit is ON when the program is transferred, loads that were
being output before program replacement will continue to be output after
replacement. Be sure that external loads will operate properly after program
replacement.
The status of force-set and force-reset bits will be maintained through the pro-
gram replacement if the Forced Status Hold Bit (A50013) is ON.
Interrupts will be masked.
If data tracing is being performed, it will be stopped.
Instruction conditions (interlocks, breaks, and block program execution) will be
initialized.
Differentiation Flags will be initialized whether the IOM Hold Bit is ON or OFF.
Operations after
Program Replacement
The status of the cyclic tasks depends upon their operation-start properties.
(Their status is the same as it would be if the PLC were switched from PRO-
GRAM to RUN/MONITOR mode.)
The First Cycle Flag (A20011) will be ON for one cycle after program execu-
tion resumes. (The status is the same as it would be if the PLC were switched
from PROGRAM to RUN/MONITOR mode.)
Time Required for
Program Replacement
Related Auxiliary Bits/Words
Size of entire program Peripheral servicing time
set in PLC Setup
Approx. time required for
program replacement
60 Ksteps Default (4% of cycle time) 6 s
250 Ksteps 25 s
Name Address Operation
File Memory Operation Flag A34313 ON for any of the following:
The CPU Unit has sent a FINS command to itself using CMND(490).
FREAD(700) or FWRIT(701) are being executed.
The program is being overwritten using an Auxiliary Area control bit
(A65015).
A simple backup operation is being performed.
Memory Card Detected Flag
(Not supported by CS-series
pre-EV1 CS1 CPU Units)
A34315 ON when a Memory Card has been detected.
IOM Hold Bit A50012 When this bit is ON, the contents of I/O memory are retained through pro-
gram replacement.
Forced Status Hold Bit A50013 When this bit is ON, the status of force-set and force-reset bits is main-
tained through program replacement.
To Next Page
Loading...
