
3. PMC I/O SIGNAL DISPLAY AND
INTERNAL RELAY DISPLAY
(PMCDGN)
B–61863E/15
PMC OPERATION (CRT/MDI)
464
CAUTION
1 In OVERRIDE mode, input/output signals are updated at
8–ms intervals in sync with the first ladder level. When an
I/O link is used which is usually updated at 2–ms intervals,
an input/output signal timing delay occurs. For this reason,
note that a sequence that depends on input/output signal
timing may perform an unpredictable operation.
2 Note that, when OVERRIDE mode is set, the interval of the
second level may be extended slightly.
3 Even if OVERRIDE is set for a Y address, the resultant value
of a ladder operation before being modified by the forced
input/output function is displayed as the coil on/off value in
ladder dynamic display.
A value, after being modified by the forced input/output
function, is output to the machine. So, note that the on/off
indication in ladder dynamic display does not match a value
output to the machine.
Example:
In this example, the forced input/output function is used
for Y0.0 in the ladder below in a configuration where the
I/O UNIT–MODEL A is connected to Y0 with an I/O link.
Before OVERRIDE setting, the on/off indication in
dynamic display matches a value output to the I/O
UNIT–MODEL A as shown below.
If 1 is entered forcibly after setting OVERRIDE for Y0.0,
the value modified by the forced input/output function is
output to the I/O UNIT–MODEL A as shown below.
I/O UNIT–MODEL A NC
Y0.0 = off
X0.0 Y0.0
(Off) (Off)
(Dynamic display)
I/O UNIT–MODEL A NC
Y0.0 = on
X0.0 Y0.0
(Off) (Off)
(Dynamic display)