Technical FAQs

Ask a Question

What safety functions are available on the ATV312 series drive?

Issue:
What safety functions are available on the ATV312 series drives?

Product Line:
ATV312 series drives

Environment:
All models, All serial numbers.

Cause:
Information not available in current literature.

Resolution:
The ATV312 have no safety function (STO is a safety function) but a study was done for each standard logic inputs to determine their safety level (which is SIL1, PLc, category 1 in "source" mode).
Different tests and calculations were performed internally for all these products and based on this; they have got reliability values for these families of drives.
--> The analysis is made without certification from a notified body

The study is split in two parts:
•    The first is to determinate the safety level for each logic inputs. The synthesis of dependability study on logic input of basic drive machine is: SIL1, PL "c", and category 1 in "source" mode (DC = 60,57%).
Safety level of the ATV312 alone
Functions in "source" mode    ATV312
  User-added image
The "sink" mode is not allowed for safety relevant functions

•    The second part is to determinate the safety level in function of the combinations 2 wires/3 wires. 
The recommendation is to be in 3 wires to be SIL1, PL "c", and category 1 in "source" mode with this remark for the 2 wires connection: "The number of push button activation generates a bad failure rate of push button and limits the safety level to a non-safe system"

ATV in application with push buttons
In some applications of basic drive module, logic input can need a safety level for standard function.
For example for crane or overhead crane applications, the direction & the hoisting commands can be consider as safe function. 
In this type of application, the architecture with 2 wires and push buttons, "source" or "sink" mode, is not recommended because the safety level of the push button is not sufficient for a standard application. 
The 3 wires connection is highly recommended in "source" mode to be SIL1, PLc and category 1.

Example:
What happen if there is no 24 VDC on LI1?

Indeed in 3 wires, if LI1 (stop) = 0 (no 24VDC), the drive will be in stop whatever the state of LI2 (forward) and LI3 (reverse).
But in 2 wires, if LI1=0 and LI2=1 then the drive will be in reverse. 

The 3 wires adds a condition which making safer control. Moreover in 2 wires, you can be in "transition" or in "level". So if you are set in "level", LI1 or LI2 =1 and there is a power off, the motor is stopped. Then when the power is back, the drive will automatically restart the motor.

If the customer considers the stop/start function as a safety function, so the recommendation is to be in 3 wires connection and in "source" mode to be SIL1, PLc, and category 1.
The 2 wires connection is not recommended but if the customer doesn't consider the stop/start function as a safety function, so there is no PL.

To keep in mind 
ATV312 will be SIL1, PL "c", and category 1 in "source" mode. The 3 wires connection is highly recommended.
ATV312 does not have safety function. The value and recommendation gave here follow an internal study for the standard logic input.
The analysis is made without certification from a notified body
Was this helpful?
What can we do to improve the information ?