Danfoss VACON OPTEA User Manual

Table 48: Description of the Parts of the Watchdog Time
Symbol
Name
Description
DAT
Device Acknowledgment Time
70 ms for the complete AC drive system
HAT
Host Acknowledgment Time
Application-specific
BT
Bus Cycle Time
The bus cycle time
The F-Parameter F WD Time must have a value that is slightly greater than the sum of DAT, HAT, and two times the bus transfer
time. It is recommended not to exceed the calculated value by more than 30%. Setting a shorter watchdog time does not have an
effect on the safety of a system, but it can cause a fault and make the AC drive trip.
For example, if HAT is 4 ms and the PROFIBUS cycle time is 3 ms, F WD Time should be set to:
FWDTime = (DAT + HAT + 2 × BT) × 1 . 3 = (70ms + 4ms + 2 × 3ms) × 1 . 3 = 104ms
For example, if HAT is 4 ms and the PROFINET cycle time is 4 ms, F WD Time should be set to:
FWDTime = (DAT + HAT + 2 × BT) × 1 . 3 = (70ms + 4ms + 2 × 4ms) × 1 . 3 = 110ms
If there is extreme electromagnetic interference, the communication systems use retry mechanisms to increase the robustness of
the system. Before setting the F WD Time, it is recommended to find the number of retries of each connection and adjust the mini-
mum watchdog time if necessary.
7.1.5.3 The PROFIsafe Safety Function Response Time (SFRT)
PROFIsafe specifies a safety function response time (SFRT), during which the safety system must react to a fault in the system. The
SFRT includes all individual delays, including the bus transfer times. All of these elements have minimum and maximum delays, and
the actual delay is likely to be somewhere in between these values. For safety reasons every communication cycle has its own
watchdog time WDTimei after which the safe state is activated if a fault occurs in that communication cycle.
To calculate the safety function response time, use this formula:
SFRT = 
∑
i = 1
n
WCDT
i
 + max
i = 1,2..,n
(WDTime
i
 − WCDT
i
)
SFRT = Safety Function Response Time
WCDTi = Worst Case Delay Time of entity i
WDTimei = Watchdog Time of entity i. See chapter 7.1.5.2 PROFIsafe Watchdog Time.
Adding the worst case delay times for components of the VACON
®
safety system gives the total Worst Case Delay Time.
Table 49: The Delays and Watchdog Times of a VACON
®
Safety System
Device
Worst case delay time
Watchdog time
The complete AC drive system
70 ms
Recommended 150 ms or larger
7.1.6 PROFIdrive on PROFIsafe
7.1.6.1 General Information on PROFIdrive on PROFIsafe
The PROFIdrive on PROFIsafe telegrams are mapped according to the PROFIdrive on PROFIsafe amendment. The selected data for
controlling the safety functions is included in the PROFIsafe frame.
For the AC drive to fully comply with PROFIdrive on PROFIsafe, a compatible drive application must be used, for example the Multi-
purpose Control Application, APFIFF06.
N O T I C E
Some values of some parameters in the Advanced safety option board are not compatible with PROFIdrive on PROFIsafe. The
Advanced safety option board allows more detailed or different behavior for some safety functions than what is mentioned in the
PROFIdrive on PROFIsafe amendment.
AQ319736045637en-000101 / DPD01798 | 115Danfoss A/S © 2021.06
Safe Fieldbuses
VACON® NXP Advanced Safety Options
Operating Guide

Danfoss VACON OPTEA Specifications

General

Brand	Danfoss
Model	VACON OPTEA
Category	DC Drives
Language	English