Application Notes For El47Xx - Beckhoff EL47 Series Documentation

Commissioning
5.9

Application notes for EL47xx

The EL47xx (EL4712, EL4732) have 2 safeguards for checking and ensuring correct data output: automatic
monitoring of cyclic data via CycleCounter and a watchdog.
Monitoring via the CycleCounter
For each output channel the EL47xx has a CycleCounter that has to be supplied with a consecutive counter
value by the task. The CycleCounters for all available channels must be served. Based on the CycleCounter
value the EL47xx can detect whether the data have arrived in the order required by the master. In the event
of a missing data packet (e.g. due to a LostFrame) or a frame repetition an internal register in the ESC
(EtherCAT slave controller) of the EL47xx is incremented by 1. By reading the 30D(hex) register the program
can detect whether the data have been output correctly. The x30D register must be read via asynchronous
EtherCAT communication, e.g. at one-second intervals.
See sample program
(https://infosys.beckhoff.com/content/1033/el47xx/Resources/zip/2409495947.zip).
Watchdog support
The EL47xx includes a watchdog that prevents uncontrolled data output. See corresponding section Notes
for setting up the watchdog [} 18]. A 100 ms watchdog is activated by default, in which case the EL47xx
behaves as follows:
• Process data arriving consecutively at the EL47xx via EtherCAT are output accordingly. Each
successful SyncManager access resets the watchdog.
• If the EL47xx has received no new data for the next output cycle it will continue to output the last
voltage, and the watchdog is triggered.
• When the set watchdog time has elapsed (default: 100 ms), the EL47xx outputs 0 V/0 mA.
• The EL47xx supports disabling of the watchdog by entering "0" in the corresponding dialog, see Notes
for setting up the watchdog [} 18].
Compatibility
EL4712
All EL4712 devices support the watchdog feature.
EL4732
Watchdog support was added in EL4732 with serial number xxxx0200 and above. This applies to the
terminals with ID EL4732-0000-0003 and above.
If a version with watchdog support is used in the configuration, older versions without watchdog support
cannot be used as terminals in this configuration.
Application without XML description
In order to ensure optimum utilization of the EL47xx with all options, we advise against parameteri-
zation without descriptive XML file, i.e. purely based on EEPROM content.
158 Version: 2.7 EL47xx