CS1D-BC042D Omron, CS1D-BC042D Datasheet - Page 308

• Manufacturer Part Number: CS1D-BC042D
• Description: CS1D Dual CPU Exp
• Manufacturer: Omron

Specifications of CS1D-BC042D

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Holding Area
8-10 Holding Area
Forcing Bit Status
Holding Area Initialization
Self-maintaining Bits
Precautions
Note
The Holding Area contains 512 words with addresses ranging from H000 to
H511 (bits H00000 to H51115). These words can be used only in the pro-
gram.
Holding Area bits can be used in any order in the program and can be used as
normally open or normally closed conditions as often as necessary.
Bits in the Holding Area can be force-set and force-reset.
Data in the Holding Area is not cleared when the PLC’s power supply is cycled
or the PLC’s operating mode is changed from PROGRAM mode to RUN or
MONITOR mode or vice-versa.
A Holding Area bit will be cleared if it is programmed between IL(002) and
ILC(003) and the execution condition for IL(002) is OFF. To keep a bit ON
even when the execution condition for IL(002) is OFF, turn ON the bit with the
SET instruction just before IL(002).
When a self-maintaining bit is programmed with a Holding Area bit, the self-
maintaining bit won’t be cleared even when the power is reset.
1. If a Holding Area bit is not used for the self-maintaining bit, the bit will be
2. If a Holding Area bit is used but not programmed as a self-maintaining bit
When a Holding Area bit is used in a KEEP(011) instruction, never use a nor-
mally closed condition for the reset input if the input device uses an AC power
supply. When the power supply goes OFF or is temporarily interrupted, the
input will go OFF before the PLC’s internal power supply and the Holding Area
bit will be reset.
Instead, use a configuration like the one shown below.
turned OFF and the self-maintaining bit will be cleared when the power is
reset.
as in the following diagram, the bit will be turned OFF by execution condi-
tion A when the power is reset.
Input
Unit
A
Set input
Reset input
H00000
Section 8-10
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