Operating modes
The EL30xx and the EL31xx accordingly supports three different operating modes: Freerun (filter on, timer interrupt), Synchron (filter off, SyncManager interrupt) and DC (DC Sync interrupt)
The terminal switches between the Freerun (filter on) and Synchron modes by activating/deactivating the filter via the index. The terminal remains in OP mode during this process. The changeover may result in longer sampling times and step changes in the process data until the filters have assumed a steady state.
DC mode can only be used when the filters are switched off. Likewise, it is not possible to switch the filters on in DC mode. The DC mode is parameterized via the DC tab in the TwinCAT System Manager.
The operating modes of the EL30xx/EL31xx are:
Mode | 1 (default) | 2 | 3 | 4 | 5 | 6 | |
|---|---|---|---|---|---|---|---|
Filter (Index: 0x8000:06) | On (default.: 50 Hz FIR) | Off | |||||
Distributed Clocks mode | Off | On | |||||
Possible with EL30xx | x | x | x | x | x |
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Possible with EL31xx | x | x | x | x | x | x | |
Default setting for | EL30xx |
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| EL31xx |
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Synchronization mode (index:0x1C33:01, bit 0+1) | 0: FreeRun (default) | 0: FreeRun (default) | 1: Frame triggered (SM3 inputs) | 3: DC mode | |||
FastOp-Mode "CoE" (Index: 0x1C33:01, bit 15) | Off (default) | Off (default) | On | Off (default) | On | Off (default) | |
StartUp entry index 0x1C33:01 | 0x0000 | 0x0000 | 0x8000 | 0x0001 | 0x8001 |
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Update frequency | depends on filter setting; automatically set inside the terminal see following values | EtherCAT cycle time, if value does not fall below the lower setting-dependent limit. See following values for typical limit. Operation with a faster EtherCAT cycle is possible, but in that case the EL30xx no longer supplies new data in each cycle. | EtherCAT cycle time, if value does not fall below the lower setting-dependent limit. | ||||
typical data update time (EL30x1) | 50 Hz FIR: typical 625 µs 60 Hz FIR: typical 520 µs IIR: typical 1 ms | < 600 µs | < 500 µs | ||||
typ. data update time (EL30x2) | |||||||
typ. data update time (EL30x4) | |||||||
typ. data update time (EL30x8) | 50 Hz FIR: typ. 1.25 ms 60 Hz FIR: typ. 1 ms IIR: typ. 1 ms | < 1.1 ms | < 1 ms | ||||
Note | If filtering is enabled, the following settings are activated in the EL30xx, |
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| The notes on the minimum EtherCAT cycle time in DC mode must be observed. | |
 | Combinations of filters, FastOp mode and Synchronization mode Other combination options of filter, FastOp mode and Synchronization mode are expressly not recommended. |
Synchron mode
In synchronous operation process data are generated frame-triggered, so that a new value is available with each PLC cycle. In the EL31xx terminals synchron mode is used automatically (filter off, no DC). The minimum cycle times are 80 µs (EL31x1/EL31x2), and 120 µs (EL31x4) for standard IPCs.
DC operation
In DC mode the process data are requested via DC interrupt. This results in the temporal jitter between two frames being equalized, so that the sampling time is uniform across the system.
The EL31xx should be operated in DC input based mode.
The DC mode requires minimum cycle times of
- 100 µs (EL31x1/EL31x2 in 1 channel mode)
- 125 µs (EL31x2 in 2 channel mode)
- 150 µs (EL31x4)
- 250 µs (EL3174)
- 200 µs (EL3174-0002, EL3174-0032)
- 500 µs (EL3174-0090)
for standard IPCs.
In input-based mode the sync interrupt is shifted automatically, so that the process data are ready just before the current process data cycle.
If the frame jitter is too large, there is still the possibility that duplicate data will be retrieved or that the transmission will be interrupted. Then the jitter must be reduced or a slower cycle time selected by TwinCAT system corrective measures.