Simplex 4007ES Panels, Programmer'S Manual

Page: 88 / 168

9-4
4007ES Panel Programmer Manual ( 579-1167)
Custom Control, Continued
Using a Ladder
Logic Diagram to
Evaluate an
Equation • Use a circle to represent each output statement. Add text within or beside the circle to
describe the output statement. In the following example, the output side of the equation
contains a single output statement, HOLD ON SIG 1. This action only occurs if the
input side of the equation, which monitors point M 2-1 for the presence of a fire
condition, is true.
• Represent the OR logical operator by positioning inputs on top of one another as
shown in the example below. Represent the AND logical operator by positioning the
inputs beside one another.
Figure 9-6. Logic Diagram
The example shown above can be interpreted as: If point M2-1 or M2-2 or M2-3 and M2-4 are
in a trouble state, hold on Relay 1. M2-4 is the key here. At least one of the three on the left
(M2-1, M2-2, and M2-3) must be in a trouble state AND M2-4 must also be in a trouble state.
Solid line
represents the
start of the
equation
Vertical, parallel
lines represent input
Dashed line
separates input side
from output side
Circles represents outputs
Hold ON
SIG1
Point Status
M 2-1 for
FIRE
Position the
inputs on
top of one
another to
represent
the OR
logical operator
Point Status
M 2-1 for TBL
Point Status
M 2-2 for TBL
Point Status
M 2-3 for TBL
Position the inputs beside
one another to represent AND
logical operator
Relay
Point Status
M 2-4 for TBL