Setting For Emergency Stop; Deceleration Control - Mitsubishi MELDAS HS Series Specifications And Instruction Manual

8-4 Setting for emergency stop

The emergency stop referred to here indicates the following states.
1) When the external emergency stop was input (including other axis alarms)
2) When the CNC power down was detected
3) When a servo alarm was detected

8-4-1 Deceleration control

This intelligent servomotor servo amplifier decelerates the motor according to the set time constant in
the ready ON state even when an emergency stop occurs, and activates the dynamic brakes after
stopping and turning ready OFF. This series of controls is called deceleration control. In the intelligent
servomotor, deceleration control is the standard method of stopping during an emergency stop.
<Features>
1) When the load inertia is large, deceleration and stop are possible with a short time constant
using the dynamic brakes. (Stopping is possible with a basically normal acceleration/
deceleration time constant.)
2) When used in a transfer line, etc., stopping with little shock is possible by setting a long time
constant.
(1) Setting the deceleration control time constant
The time to stopping from the rapid traverse rate (rapid: axis specification parameter) is set in the
deceleration control time constant (SV056: EMGt). A position loop step stop is carried out when 0
is set.
When linear (straight line) acceleration/deceleration is selected for the rapid traverse, the same
value as the acceleration/deceleration time constant (G0tL) becomes the standard value. When
another acceleration/deceleration pattern is selected, set the rapid traverse to linear
acceleration/deceleration. Adjust to the optimum acceleration/deceleration time constant, and set
that value as the standard value.
<Operation>
When an emergency stop occurs, the motor will decelerate at the same inclination from each
speed, and will change to the dynamic brakes at 60 r/min or less. If the power fails, etc., the
dynamic brakes will be applied during the deceleration control. When the motor brakes are
controlled with amplifier output while using an unbalanced axis, the motor brake control output
operates simultaneously with the changeover to the dynamic brakes.
Dynamic brakes
Motor brake control output (MBR)
No. Abbrev. Parameter name
SV056 EMGt Deceleration control
time constant
POINT
Chapter 8 Adjustment
RAPID
Motor speed
OFF
ON
OFF
ON
Unit
Set the time to stop from rapid traverse rate (rapid).
msec
Set the same value as the rapid traverse
acceleration/deceleration time constant (G0tL) as a standard.
1. The deceleration will not be controlled when a servo alarm that uses the
dynamic brake stopping method occurs. Stopping is by the dynamic brake
method regardless of the parameter setting.
2. When a power failure occurs, the stopping method may change over to a
dynamic brake stop during deceleration control if the deceleration time
constant is set comparatively long. This is because of low bus voltage in the
amplifier.
Emergency stop occurrence
Constant inclination deceleration
Dynamic brakes activate at 60 r/min or less
EMGt
Explanation
8–24
Time
Setting range
0 to 5000