Sto Function; Fault, Warning And Alarm Functions; Operation At Overtemperature - Danfoss VLT AQUA Drive FC 202 Design Manual

Product Overview
The logic rules, timers, and comparators are also available
for use outside of the SLC sequence.
For an example of SLC, refer to chapter 4.3 Application Set-
up Examples.3

2.6.16 STO Function

The adjustable frequency drive is available with STO
functionality via control terminal 37. STO disables the
control voltage of the power semiconductors of the
adjustable frequency drive output stage. This in turn
prevents generating the voltage required to rotate the
motor. When the STO (terminal 37) is activated, the
adjustable frequency drive issues an alarm, trips the unit,
and coasts the motor to a stop. Manual restart is required.
The STO function can be used as an emergency stop for
the adjustable frequency drive. In the normal operating
mode when STO is not required, use the regular stop
function. When using automatic restart, ensure the
requirements of ISO 12100-2 paragraph 5.3.2.5 are fulfilled.
Liability conditions
It is the responsibility of the user to ensure personnel
installing and operating the STO function:
•
Read and understand the safety regulations
concerning health, safety, and accident
prevention.
•
Have a good knowledge of the generic and safety
standards applicable to the specific application.
A user is defined as:
•
Integrator
•
Operator
•
Service technician
•
Maintenance technician
Standards
Use of STO on terminal 37 requires that the user satisfies
all provisions for safety including relevant laws, regulations
and guidelines. The optional STO function complies with
the following standards:
•
EN 954-1: 1996 Category 3
•
IEC 60204-1: 2005 category 0 – uncontrolled stop
•
IEC 61508: 1998 SIL2
•
IEC 61800-5-2: 2007 – STO function
•
IEC 62061: 2005 SIL CL2
•
ISO 13849-1: 2006 Category 3 PL d
•
ISO 14118: 2000 (EN 1037) – prevention of
unexpected startup
MG20N622
Design Guide
The information and instructions here are not sufficient for
a proper and safe use of the STO functionality. For full
information about STO, refer to the VLT
Instruction Manual.
Protective measures
•
•
•
•

2.7 Fault, Warning and Alarm Functions

The adjustable frequency drive monitors many aspects of
system operation including line power conditions, motor
load and performance, as well as drive status. An alarm or
warning does not necessarily indicate a problem with the
adjustable frequency drive itself. It may be a condition
outside of the drive that is being monitored for
performance limits. The drive has various pre-programmed
fault, warning and alarm responses. Select additional alarm
and warning features to enhance or modify system
performance.
This section describes common alarm and warning
features. Understanding that these features are available
can optimize a system design and possibly avoid
introducing redundant components or functionality.

2.7.1 Operation at Overtemperature

By default, the adjustable frequency drive issues an alarm
and trip at overtemperature. If Autoderate and Warning is
selected, the adjustable frequency drive will warn of the
condition but continue to run and attempt to cool itself by
first reducing its switching frequency. Then, if necessary, it
reduces the output frequency.
Autoderating does not replace the user settings for
derating for ambient temperature (see chapter 5.3 Derating
for Ambient Temperature).
Danfoss A/S © 09/2014 All rights reserved.
Qualified and skilled personnel are required for
installation and commissioning of safety
engineering systems.
The unit must be installed in an IP54 cabinet or
in an equivalent environment. In special
applications, a higher IP degree is required.
The cable between terminal 37 and the external
safety device must be short-circuit protected
according to ISO 13849-2 table D.4.
When external forces influence the motor axis (for
example, suspended loads), to eliminate potential
hazards, additional measures are required (for
example, a safety holding brake).
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Safe Torque Off
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