Iom Hold Bit Startup Hold Setting - Omron CJ2 CPU - REV 10-2010 User Manual

9 PLC Setup
OFF: Forced Status Hold Bit cleared at startup
Mode switch
ON: Forced Status Hold Bit protected at startup
Mode switch Retained

IOM Hold Bit Startup Hold Setting

Use this parameter to set whether to retain the status of the IOM Hold Bit in the Auxiliary Area at
startup.
Parameter
IOM Hold Bit OFF: Cleared
Startup Hold
ON: Retained
Setting
• Relation between IOM Hold Bit and this Parameter
The IOM Hold Bit (A500.12) can be turned ON to retain all of the data in I/O memory when the CPU
Unit's operating mode is switched from PROGRAM mode to RUN or MONITOR mode, and vice
versa. When the PLC is turned ON, the IOM Hold Bit itself will be turned OFF unless it is protected
with this PLC Setup setting.
If the IOM Hold Bit Status at Startup setting is ON, the status of the IOM Hold Bit will be protected
when the PLC is turned ON. If this parameter is set to ON and the IOM Hold Bit itself is ON, all data
in I/O memory will be retained when the PLC is turned ON.
If the memory is not retained because the battery voltage is low, the IOM Hold Bit will be cleared
whether this parameter is set to ON or OFF.
9-6
Power
Forced bit status
OFF
Retained
Forced Status
Hold Bit: ON
Power
Forced bit status
OFF
Forced Status
Hold Bit: ON
Settings Default
OFF This setting determines whether the status of the
IOM Hold Bit (A500.12) is retained at startup.
When you want all of the data in I/O Memory to
be retained when the power is turned on, turn ON
the IOM Hold Bit and set this setting to ON.
Power
Forced bit status
ON
Power ON Not retained
Forced Status
Not retained
when power is
Hold Bit: OFF
turned ON.
Power
Forced bit status
ON
Retained
Power ON
Retained when
Forced Status
power is turned
Hold Bit: ON
ON.
Function
CJ2 CPU Unit Software User's Manual
Related flags
and words
A500.12 (IOM
Hold Bit)