KPA EtherCAT Master Stack Architecture

EtherCAT master stack has a modular structure to respond to a challenge of each particular implementation. It makes the master scalable to fit the size of application, portable to different operating systems, adaptable to various hardware platforms and allows developing or customizing each module separately while keeping the functionality of the others intact.

Master’s modules are grouped in the following layers, thereby all functions are clearly separated:

Application layer

Application layer is responsible for interaction with various programming or/and configuration environments and other applications or devices. It encapsulates and

• ensures access to master’s functions from the side of applications or process tasks.
• allows interaction with the master by means of Remote Procedure Calls service and provides TCP/IP or/and UDP connections, for example, for mailbox communication with slaves via UDP

KPA EtherCAT Master Stack Core

Mailbox module

KPA Master Core mailbox module deploys protocols to handle service data objects (SDP), data transfer and data exchange. The following protocols – according to the EtherCAT standard – are already supported:

• CAN application protocol over EtherCAT (CoE)
• Ethernet over EtherCAT (EoE)
• Servo Profile over EtherCAT (SoE)
• File Access over EtherCAT (FoE)
• Vendor specific Profile over EtherCAT (VoE)
• ADS over EtherCAT (AoE)

Process Image Module

Process Image addresses are provided by EtherCAT network information (ENI) file, generated by a configuration tool. Access to the process image from control/process tasks is carried out through the master interface.

Distributed Clocks Module

Frame Scheduler Module – Different Scan Rates for PDO

In the configuration tool the user defines scan rates for each slave individually. Frame Scheduler module manages velocity of EtherCAT frames by forwarding them to EtherCAT network driver.

KPA EtherCAT Master Stack OSAL

Operating System abstraction layer (OSAL)

Master Stack OSAL allows making the master portable to any operating system with less effort.

The layer consists of two modules:

• OS functions module contains wrappers for OS-dependent functions that deal with threads, timers, mutexes, etc.
• Network adapter driver module that abstracts the master stack core from the underlying network implementation.

KPA EtherCAT Master Operating Systems

Notes: Some OSes like Windows XP, CE6/7, OnTime RTOS-32, PikeOS, RTAI are ported, but not actively supported. any other OS can be supported on request.

KPA EtherCAT Master Stack Benchmark

Config “Simple”:
64Bytes Frame, 1 LRD / 1 LWR, No DC, No Mailbox (EK1100 – EL1004 – EL2004)

Config “Complex”:
1 Full frame (1514Bytes frame for PDO), LRD / LWR commands, DC, Mailbox via EVENT (EK1100-EL1004-EL2004-EL1252-EL3102-EL4102-EL6751-EL6751)

Test Platform:
CPU: Intel® Core i7-3770 CPU 3.40 GHz 3.39GHz
NIC: Intel® Gigabit CT desktop adapter
RAM: 8GB

1. Comparing Master performance results running on different RTOSes but on the same target Intel Core i7 (Single CPU core for all Master threads)

Master cycle time, µs	100	100	100	100	100
Jitter, ±µs	5	2	7	10	1
Slave response time (avg), µs	43	32	43	33	22
CPU load (avg), %	16	21	21	21	13,3

Config “Complex”:

Master cycle time, µs	200	200	200	200	200
Jitter, ±µs	4	2	3	4	1
Slave response time (avg), µs	170	150	171	166	154
CPU load (avg), %	10	12	13	13	3,8

2. Best Master performance results running on different RTOSes but on the same target (Single CPU core for all Master threads)

Config “Simple”:

Master cycle time, µs	50	50	100	100	50
Jitter, ±µs	10	3	7	10	1
Slave response time (avg), µs	43	32	43	33	22
CPU load (avg), %	31	41	21	21	27,5

Master cycle time, µs	200	200	200	200	200
Jitter, ±µs	4	2	3	4	1
Slave response time (avg), µs	170	150	171	166	154
CPU load (avg), %	10	12	13	13	3,8

KPA EtherCAT Master Stack Packages

Master Classes

Each package contains a specific set of functions and features divided into classes, so you can select a master of the class that fits your application to perfection. The comparison matrix below (PDF-File) shows the differences between Basic (Class B) and Standard (Class A) options.

  KPA EtherCAT Master Classes Flyer (190.4 KiB, 900 hits)

Feature Packs and Extensions

In addition to these classes, you can select Master Feature Packs and KPA Master from the following list:

Master Feature Packs

• Cable Redundancy
• Hot Connect
• TCP/UDP Mailbox Gateway
• External Synchronization

KPA Master Extensions

• Data- and Frame-Logger
• Access Rights
• Multi Master (Master 1.6)
• Extended Master Diagnostics (Master 1.6)
• Database CAN (DBC)
• Master OD
• EtherCAT Automation Protocol (EAP)
• Online configuration
• Data cashing

Operating Systems

On the third step, you can select the Operating System