7-4
7.4.1 Symbols
Table 7.4 lists the meanings of symbols used in Figure 7.1.
Table 7.4 Symbol Details
Symbol Name
Function
code
Descriptions
This specifies the start position data for the positioning control. It can be
the current position [P] (absolute position) or numerical value (relative
position). Specification of an absolute position and that of a relative
position produce different results as described below.
[Absolute position]
Specifying [P] regards the current position as a start point. When starting
the positioning control, the inverter applies the current position pulse
count as start point data.
(Example) Suppose that the current position pulse count = 10,000, the
start point data = [P], and the stop point (E point) pulse count = 20,000.
Then, when starting the positioning control, the inverter moves the control
object from the current position (10,000, as start point data) to the E point
(20,000). Accordingly, the object moving pulse count is 10,000 (20,000 -
10,000).
S point
Start point J74, J75
[Relative position]
Specifying "a" (numerical value) substitutes "a" for the current position
data. When starting the positioning control, the inverter applies "a" pulses
as start point data.
(Example) Suppose that the current position pulse count = 10,000, start
point data "a" = 4,000, and the stop position (E point) pulse count =
20,000.
Then, when starting the positioning control, the inverter moves the control
object from the start point pulse count "a" (4,000) instead of the current
position data (10,000) to the E point (20,000). Accordingly, the object
moving pulse count is 16,000 (20,000 - 4,000).
ST
Start timer J73
This specifies the waiting time from when a run command comes ON with
the S/R terminal command being ON until the inverter starts running the
motor. (This covers the delay of brake OFF.)
If the output frequency has not been zero (inverter running), turning the
terminal command S/R ON does not start the timer count. (During
deceleration triggered by turning the run command OFF, the start timer
does not start as well.)
Z point
Preset
position
J76, J77
When the inverter detects that the Z signal is turned from Low to High first
after the LS terminal command is turned from OFF to ON, it corrects the
current position data for the preset position data (Z point). This is
functionally equivalent to a mechanical position correction or origin point
reset.
Specifying [P] to the preset position does not perform the Z point
correction.
It is also possible to restrict the application of the Z point correction with
the LS to the motor rotational direction specified by function code J87.
L
Creep speed
switch point
J78,
J79
This specifies an absolute position pulse count required from a
deceleration start point (towards the creep speed specified by J80) to the
E point.
CP
Coasting
correction
J85
This specifies the deceleration start point that follows the end of
creep-speed operation. Specify it with the pulse count from the E point.
Take into account the inertia produced when the control object
decelerates to stop.
E point End point
J81, J82
This specifies a target stop position.
ER
Positioning
allowance
J83
This specifies the positioning allowance at the E point, that is, "Actual stop
position - E point position."
After the end timer counts up:
If "Actual stop point - E point " ≤ ER, the inverter issues the "Positioning
completed" signal PSET.
If "Actual stop point - E point " > ER, the inverter issues the "Stop point
alarm" signal OT.
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