Mitsubishi Electric MELSEC-L02SCPU User Manual page 101

(2) Precautions
(a) Selection of external command signal
An attempt to start speed/position switching control without selecting an external command signal generates a
"Speed/position switching control start not possible" error (Axis 1 error code: 1505).
(b) External command signal on timing and operation
• If speed/position switching control is started while the external command signal is still on, position control
is implemented first. (The Axis 1 current feed value (SD1840, SD1841) is cleared to 0 and then refreshed
accordingly thereafter.)
• If the external command signal is turned on before the command speed is reached, position control is
implemented at the speed effective at that point.
(c) External command signal and positioning data
If the following condition is met, deceleration starts at the moment an external command signal is input:
Positioning address/movement amount < Deceleration distance from command speed
In this case, the axis moves only by the movement amount set by "Positioning address/movement amount,"
before decelerating to the bias speed at start, and then stops immediately.
(d) Speed 0
When the bias speed at start is set to 0 and the command speed is also set to 0 under the speed control,
operation does not start. At this time, the special relays and registers assume the following status. To continue
with the operation, set a value other than 0 for the new speed value and then turn off the Axis 1 speed 0
(SM1844) using a speed change request with the Speed change instruction (IPSPCHG1(P)).
• Axis 1 speed 0 (SM1844): On
• Axis status: Stop
• Axis 1 axis operation status (SD1844): 5 (In speed-position control (speed))
• Axis 1 busy (SM1840): On
If the bias speed at start is other than 0, changing the command speed to 0 generates an "Out of speed range"
warning (Axis 1 warning code: 1020) and the axis operates at the bias speed at start.
(e) Software stroke limit
Do not implement speed/position switching control beyond the range of software stroke limits. If the value of
"Positioning address/movement amount" exceeds the range of software stroke limits during speed control, a
"Software stroke limit+" error (Axis 1 error code: 1103) or "Software stroke limit-" error (Axis 1 error code: 1104)
occurs the moment it switches to position control, and the axis decelerates to a stop.
(f) Set value of "Positioning address/movement amount"
Do not set a negative value for "Positioning address/movement amount." A "Movement amount setting out of
range under speed/position switching control" error (Axis 1 error code: 1504) occurs.
(g) Stop position
To suppress fluctuation of the stop position after switching to position control, turn the external command signal
on in a stable speed area.
CHAPTER 7 POSITIONING FUNCTION
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