CPU
S
pecifications
and
Operation
4--12
CPU Specifications and Operation
DL105 PLC User Manual, 3rd Edition
In Program Mode, the CPU does not
execute the application program or update
the output points. The primary use for
Program Mode is to enter or change an
application program. You also use
program mode to set up the CPU
parameters, such as HSIO features,
retentive memory areas, etc.
You can use a programming device, such
as
Direct
SOFT or the D2--HPP Handheld
Programmer to place the CPU in Program
Mode.
Download
Program
In Run Mode, the CPU executes the
application program and updates the I/O
system. You can perform many operations
during Run Mode. Some of these include:
S
Monitor and change I/O point status
S
Update timer/counter preset values
S
Update Variable memory locations
Run Mode operation can be divided into
several key areas. For the vast majority of
applications, some of these execution
segments are more important than others.
For example, you need to understand how
the CPU updates the I/O points, handles
forcing operations, and solves the
application program. The remaining
segments are not that important for most
applications.
You can use
Direct
SOFT or the D2--HPP
Handheld Programmer to place the CPU
in Run Mode.
Read Inputs
Solve the Application Program
Write Outputs
Diagnostics
Update Special Relays
Service Peripherals
Normal Run mode scan
You can also edit the program during Run Mode. The Run Mode Edits are not
“bumpless” to the outputs. Instead, the CPU maintains the outputs in their last state
while it accepts the new program information. If an error is found in the new program,
then the CPU will turn all the outputs off and enter the Program Mode. This feature is
discussed in more detail in Chapter 8.
WARNING: Only authorized personnel fully familiar with all aspects of the
application should make changes to the program. Changes during Run Mode
become effective immediately. Make sure you thoroughly consider the impact
of any changes to minimize the risk of personal injury or damage to
equipment.
Program Mode
Run Mode
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...