Danfoss VLT Series Programming Manual page 90

Servo Drive Operation
2 2
Standstill not
reached
Illustration 2.136 Standstill Reached Window
2.7.5 Constant Velocity Detection
The constant velocity detection function offers the
possibility to define a symmetrical range of accepted
velocity changes (see chapter 7.22.3.1 Parameter 51-70:
Constant Velocity Window (0x2030)), relative to the last
velocity. If the velocity of a servo drive is within this area
for a specified time, the constant velocity window time
(see chapter 7.22.3.2 Parameter 51-71: Constant Velocity
Window Time (0x2031)), the servo drive is regarded to be
running at constant velocity.
The working principle is the same as for standstill
detection (see chapter 2.7.4 Standstill Detection).
2.7.6 STO and Brake Status
The voltage is checked against a defined threshold (by the
hardware) and the state is made available to the
application for utilization with the DS402 state machine.
The safety functionality itself is not part of the software.
The STO (Safe Torque Off) voltage state influences the
DS402 state machine. The servo drive cannot be operated
if the STO voltage is not active.
If the servo drive receives the command to enter DS402
state Operation enabled, it checks if the STO voltage is
present or not. If it is not present, the servo drive enters
state Fault and signals the occurrence of an error as
described in chapter 2.7.1 Errors and Warnings.
If the servo drive is already in DS402 state Operation
enabled, it continuously monitors whether the STO voltage
is present or not. If it is not present, the servo drive enters
state Fault and signals the occurrence of an error as
described in chapter 2.7.1 Errors and Warnings.
The error code used for these 2 situations is the same and
is detailed in chapter 9.2.1 Troubleshooting. STO information
is available in objects 0x6041 (see chapter 7.3.1 Parameter
16-03 Statusword (0x6041)) and 0x2007 (see
chapter 7.22.8 Parameter 50-09: STO Voltage and Brake Status
(0x2007)).
88
®
VLT
Accepted standstil
range
Velocity Velocity
threshold threshold
Standstill not
Standstill reached
reached
0
Danfoss A/S © 01/2017 All rights reserved.
®
Integrated Servo Drive ISD 510 System
Velocity
MG36D102