Chapter 4. Ladder Diagram (LD) Programming
GFK-2950C
February 2018
89
Positive Transition Coil (PTCOIL)
Negative Transition Coil (NTCOIL)
If:
■
the
transition
bit is OFF, and
■
the input power flow is ON
the PTCOIL sets the r
eference
bit and transition
bit of its associated variable ON.
If:
■
the
transition
bit is OFF, and
■
the input power flow is OFF
the NTCOIL sets the reference bit and transition
bit of its associated variable ON.
The
transition bit
depends on the value of the input power flow the last time the PTCOIL or NTCOIL
was executed.
Notes:
■
As soon as a PTCOIL or NTCOIL is set to ON or OFF, it updates its transition bit.
■
Multiple instances of PTCOIL and/or NTCOIL can be associated with the same BOOL variable,
but the transition status of each instance of the PTCOIL or NTCOIL associated with the BOOL
variable is unique, that is, it is tracked independently.
■
The transition bit is non-retentive, that is, it is cleared to OFF when the CPU transitions from
STOP Mode to RUN Mode. As a result, the first time a PTCOIL executes with its input power
flow set to ON its associated BOOL variable will be set to ON.
Operands for PTCOIL and NTCOIL
Parameter Description
Allowed Operands
Optional
BOOL_V
The variable associated with
PTCOIL or NTCOIL
Variables in I, Q, M, T, SA, SB, SC, or G memories as
well as symbolic discrete variables. In addition, bit-in-
word references on any non-discrete memory (e.g.,
%R) or on symbolic non-discrete variables are
allowed.
No
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