EL1xxx

Scope

Use this page for EL1xxx digital-input terminals with special timing or signal level behavior.

EL1262 oversampling and NELM

The EL1262 transfers its oversampled digital inputs as packed bytes. Therefore, for this terminal, NELM specifies the number of bytes per channel and per EtherCAT cycle, not the number of individual digital samples.

The actual oversampling factor is:

oversampling factor = NELM * 8

For example, NELM=1 transfers one byte containing eight time-ordered input bits, so it configures 8-times oversampling. NELM=125 transfers 125 bytes and corresponds to the maximum factor of 1000 samples per EtherCAT cycle.

# 8-times oversampling (8 bits per channel and EtherCAT cycle):
${SCRIPTEXEC} ${ecmccfg_DIR}addSlave.cmd, "SLAVE_ID=16, HW_DESC=EL1262, NELM=1"

# 1000-times oversampling (125 packed bytes per channel and EtherCAT cycle):
${SCRIPTEXEC} ${ecmccfg_DIR}addSlave.cmd, "SLAVE_ID=16, HW_DESC=EL1262, NELM=125"

At an EtherCAT rate of 1 kHz, NELM=125 therefore produces an effective digital-input sampling rate of 1 MHz. The corresponding sample period is calculated using NELM * 8, not NELM alone.

For the EL1262, valid NELM values are byte counts in the range 1 through 125. The waveform elements are packed bytes; each element contains eight consecutive digital input samples.

EL1252, EL1252-0050

EL1252-xxxx is a two-channel digital-input terminal with timestamps for both low-to-high and high-to-low edges:

  • EL1252: 24V signals
  • EL1252-0050: 5V signals

Both terminals have the same product ID and process data and can therefore be configured as EL1252:

# One channel:
${SCRIPTEXEC} ${ecmccfg_DIR}addSlave.cmd, "SLAVE_ID=16, HW_DESC=EL1252"

These terminals are useful because they can latch the timestamp of the positive edge and/or negative edge of an input signal independently of the EtherCAT bus rate. These timestamps can then be correlated with other timestamped data, such as encoder or analog-input signals.

IMPORTANT Since the EL1252-0050 is a 5V terminal, it must be powered with 5V. If it is powered with 24V, it will most likely be damaged. The simplest way to get the correct supply is to add an EL9505 or similar terminal before the EL1252-0050.

See ELxxxx for more information about terminal power levels.

Make sure the EL1252-0050 has a 5V power supply from an EL9505 (or similar) before powering the system. If the terminal is powered with the normal 24V it will most likely break.

A 5V signal will not be detected by the 24V version (EL1252), but the terminal will not be damaged. Conversely, it is also not a good idea to power the 24V version from an EL9505 or similar 5V supply.