Changing Modes in the DL205 PLC
There are two ways to change the CPU mode. You can use the CPU mode switch to select
the operating mode, or you can place the mode switch in the TERM position and use a
programming device to change operating modes. With the switch in this position, the CPU
can be changed between Run and Program modes. You can use either
Direct
SOFT or the
Handheld Programmer to change the CPU mode of operation. With
Direct
SOFT use the
PLC menu option
PLC > Mode
or use the
Mode
button located on the Online
toolbar. With the Handheld Programmer, you use the MODE key.
Mode of Operation at Power-up
The DL205 CPUs will normally power-up in the mode that it was in just prior to the power
interruption. For example, if the CPU was in Program Mode when the power was
disconnected, the CPU will power-up in Program Mode (see warning note below).
WARNING: Once the super capacitor has discharged, the system memory may not retain the previous
mode of operation. When this occurs, the PLC can power-up in either Run or Program Mode if the
mode switch is in the term position. There is no way to determine which mode will be entered as the
startup mode. Failure to adhere to this warning greatly increases the risk of unexpected equipment
startup.
The mode which the CPU will power-up in is also determined by the state of System
Memory bit B7633.13. If the bit is set and the Mode Switch is in the TERM position, the
CPU will power-up in RUN mode. If B7633.13 is not set with the Mode Switch in TERM
position, then the CPU will power-up in the state it was in when it was powered-down.
DL205 User Manual, 4th Edition, Rev. B
3–13
Chapter 3: CPU Specifications and Operations
1
2
3
4
5
6
7
8
9
10
11
12
13
14
A
B
C
D
Mode Switch Position
CPU Action
RUN (Run Program)
CPU is forced into the RUN mode if no errors are encountered.
No changes are allowed by the attached
programming/monitoring device.
TERM (Terminal) RUN
PROGRAM and the TEST modes are available. Mode and
program changes are allowed by the programming/monitoring
device.
STOP
CPU is forced into the STOP mode. No changes are allowed by
the programming/monitoring device.
PLC Menu
MODE Key