Basics communication
EL6751
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Version: 3.5
1/25 MHz * (watchdog mult 2) = 100 µs (for default setting of 2498 for the multiplier)
The standard setting of 1000 for the SM watchdog corresponds to a release time of 100 ms.
The value in mult 2 corresponds to the number of basic 40 ns ticks representing a watchdog tick.
The multiplier can be modified in order to adjust the watchdog time over a larger range.
Example "Set SM watchdog"
This checkbox enables manual setting of the watchdog times. If the outputs are set and the EtherCAT
communication is interrupted, the SM watchdog is triggered after the set time and the outputs are erased.
This setting can be used for adapting a terminal to a slower EtherCAT master or long cycle times. The
default SM watchdog setting is 100 ms. The setting range is 0..65535. Together with a multiplier with a range
of 1..65535 this covers a watchdog period between 0..~170 seconds.
Calculation
Multiplier = 2498 → watchdog base time = 1 / 25 MHz * (2498 + 2) = 0.0001 seconds = 100 µs
SM watchdog = 10000 → 10000 * 100 µs = 1 second watchdog monitoring time
CAUTION
Undefined state possible!
The function for switching off of the SM watchdog via SM watchdog = 0 is only implemented in terminals
from version -0016. In previous versions this operating mode should not be used.
CAUTION
Damage of devices and undefined state possible!
If the SM watchdog is activated and a value of 0 is entered the watchdog switches off completely. This is
the deactivation of the watchdog! Set outputs are NOT set in a safe state, if the communication is inter-
rupted.
4.4
CoE Interface
General description
The CoE interface (CANopen over EtherCAT) is used for parameter management of EtherCAT devices.
EtherCAT slaves or the EtherCAT master manage fixed (read only) or variable parameters which they
require for operation, diagnostics or commissioning.
CoE parameters are arranged in a table hierarchy. In principle, the user has read access via the fieldbus.
The EtherCAT master (TwinCAT System Manager) can access the local CoE lists of the slaves via
EtherCAT in read or write mode, depending on the attributes.
Different CoE parameter types are possible, including string (text), integer numbers, Boolean values or larger
byte fields. They can be used to describe a wide range of features. Examples of such parameters include
manufacturer ID, serial number, process data settings, device name, calibration values for analog
measurement or passwords.
The order is specified in 2 levels via hexadecimal numbering: (main)index, followed by subindex. The value
ranges are
• Index: 0x0000 …0xFFFF (0...65535
dez
)
• SubIndex: 0x00…0xFF (0...255
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)
A parameter localized in this way is normally written as 0x8010:07, with preceding "x" to identify the
hexadecimal numerical range and a colon between index and subindex.
The relevant ranges for EtherCAT fieldbus users are:
• 0x1000: This is where fixed identity information for the device is stored, including name, manufacturer,
serial number etc., plus information about the current and available process data configurations.
