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9
Table 9-1. Statement List Language Basic Elements - Continued
Graphic
Symbol
OUT+
—(↑)—
OUT—
—(↓)—
OUT
BLK
Description
Key Sequence
OFF-ON
transitionalcoil
(one shot) on
power flow
OUTM
ON-OFF
transitionalcoil
(one shot) on no
power flow
OUTM
Return to previous
LD BLK marker
OUT
OUT
OUT
OUTM
–
+
–
+
BLK
Operation
If the output associated with
a positive transition coil is
OFF, when the coil receives
power flow it will be set to
ON for one sweep. This coil
can be used as a one-shot.
–
+
If the output associated with
this coil is OFF, when the coil
stops receiving power flow,
the reference will be set to
ON for one sweep.
Return the logic to a point
within the rung marked by
the LD BLK instruction.
Entering a Program
When entering a program each of the basic symbols contacts, coils, and function blocks
are entered into program memory locations called steps. Each step has a number
starting with one at the beginning of the program and incrementing in sequential order
until the last element in the program has been entered.
When the CPU solves the logic it starts at step one and proceeds sequentially to the
highest step number then starts over (see Chapter 2 in the Series 90-30 PLC Reference
Manual, GFK-0467, for more information).
For each instruction step you will need to indicate an instruction type. This can be a
basic element or a standard function block i.e.: AND, OR_, Function 10, etc. Also a
companion operand, in most cases, must be provided. For a basic element this operand
would be the discrete memory type (I, Q, M, T, G, S, SA, SB, SC) followed by its reference
numbered address location within this memory type. In the case of a function block the
operand would be one or more parameters. Each parameter could be an internal CPU
reference address or a constant.
GFK-0402G
Chapter 9 Statement List Programming Language
9-5