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FX Series Programmable Controlers Applied Instructions 5
5-74
Points to note:
a) FX users ma
y
set the operation mode of the
RAMP instruction b
y
controllin
g
the state of
special auxiliar
y
rela
y
M8026. When M8026 is
OFF, the RAMP instruction will be in repeat
mode. This means when the current value of D
equals S2the RAMP instruction will
automaticall
y
reset and start a
g
ain, i.e. the
contents of D will be reset to that of S1 and the
device D+1 (the number of current scans) will
reset to ‘0’ (zero). This is shown in the dia
g
ram
opposite.
When M8026 is set ON, FX users will be
operatin
g
the RAMP instruction in ‘Hold mode’.
This means once the current value of D equals
that of S2, the RAMP instruction will ‘freeze’ in
this state. This means the M8029 will be set
ON for as lon
g
as the instruction remains
ener
g
ized and the value of D will not reset until
the instruction is re-initialized, i.e. the RAMP
instruction is turned from OFF to ON a
g
ain.
b) Users of FX0 and FX0N PLC’s cannot chan
g
e the operatin
g
mode of the RAMP instruction.
For these PLC’s the mode is fixed as in the same case as FX PLC’s when M8026 has been
set ON, i.e. HOLD mode.
c) If the RAMP instruction is interrupted before completion, then the current position within the
ramp is ‘frozen’ until the drive si
g
nal is re-established. Once the RAMP instruction is re-
driven re
g
isters D and D+1 reset and the c
y
cle starts from its be
g
innin
g
a
g
ain.
d) If the RAMP instruction is operated with a constant scan mode, i.e. D8039 is written to with
the desired scan time (sli
g
htl
y
lon
g
er than the current scan time) and M8039 is set ON. This
would then allow the number of scans n (used to create the ramp between S1and S2) to be
associated to a time. If 1 scan is equal to the contents of D8039 then the time to complete
the ramp is equal to n
×
D8039.
X0
[S2]
M8029
[D]
[S1]
X0
[S2]
[S1]
M8029
[D]
The RAMP instruction ma
y
also be used with special M fla
g
s M8193 and M8194 to mimic the
operation of the SER (FNC 61) and RS (FNC 80) respectivel
y
when bein
g
pro
g
rammed on
older versions of pro
g
rammin
g
peripherals. See pa
g
e 1-5 for more details.