Calculation Of The Control Cycle Time; Control Cycle Times When Cascading Data Transmission Paths - Leuze electronic DDLS 538 S2 Series Original Operating Instructions

EtherCAT
7.4.1

Calculation of the control cycle time

NOTICE
When installing an EtherCAT data transmission path, the calculated minimum control cycle time
must be adhered to.
Ä The actual control cycle time must be greater than or equal to the calculated minimum cycle
time.
Ä The DDLS 538 ... S2 ... must not be used for control cycle times that are shorter than the
calculated minimum control cycle time.
Calculation of the minimum cycle time
Minimum cycle time = 5 ms / defined value of the Lost Frames counter of the control.
Examples:
• PLC with defined value for Lost Frames counter 10
Minimum cycle time = 5 ms / 10 = 500 µs
• NC with defined value for Lost Frames counter 3
Minimum cycle time = 5 ms / 3 = 1666 µs

Control cycle times when cascading data transmission paths

For the calculation of the cycle times with cascading, a distinction must be made as to whether or not an
EtherCAT slave participant is installed between the two data transmission paths (see chapter 7.4.2 "Control
cycle times when cascading data transmission paths").
• When cascading with an EtherCAT slave participant between the data transmission paths, the mini-
mum control cycle times are calculated as specified.
• When cascading without an EtherCAT slave participant between the data transmission paths, the cal-
culated minimum cycle times of the given used control are doubled.
Behavior if the value for the released cycle times is not met
If the calculated cycle time is not met by the used control, signaling of an interrupted network topology
through the data transmission path to the preceding EtherCAT participant cannot occur in good time (see
chapter 7.4.3 "Operationally related interruption of the EtherCAT communication").
As a result, the Lost Frames counter will reach the defined value and the Operational operating state of the
EtherCAT master will be deactivated.
NOTICE
EtherCAT participants not addressable!
If the EtherCAT master exits the Operational operating state, the sensors and actuators are no
longer actuated.
For moving machine or system parts, this can result in an emergency stop of all axes.
NOTICE
After rectifying a network interruption, the DDLS 538 ... S2 ... is immediately ready for Ether-
CAT data transmission.
TwinCAT cyclically attempts to set the EtherCAT master to the Operational operating state.
In doing so, the EtherCAT master runs through the Init > Pre-Operational > Safe-Operational >
Operational operating states.
In the Operational operating state of the EtherCAT master, the EtherCAT participants are again
addressable.
Leuze electronic GmbH + Co. KG DDLS 538 ... S2 ... 56