Beckhoff / EtherCAT Terminals

Every terminal draws E-bus current and the coupler supplies 5 V at 2 A. Add enough terminals to a working station and the far end starts dropping off the bus, which looks exactly like a faulty terminal.

EL terminals are the Beckhoff EtherCAT I/O range. The numbering is systematic, so most of the catalogue can be read without a reference.

Reading an EL number

So EL1008 is a digital input with 8 channels, and EL3054 is an analogue input with 4 channels.

Digital input, EL1xxx

Beckhoff describes the EL1008 as acquiring binary 24 V control signals and transmitting them in an electrically isolated form to the higher-level automation unit, with each channel indicating its state via an LED.

The filter time matters more than the channel count

The EL1008 has a 3 ms input filter and the EL1018 has a much faster one. Both are 8-channel 24 V digital inputs.

So they are not interchangeable on a fast application. If a machine counts pulses or captures a short event on a digital input, the filter time is the whole point of the part.

And the reverse: a fast terminal on a noisy input may read contact bounce that a filtered one would have ignored.

Check the existing number rather than matching on channels and voltage.

Digital output, EL2xxx

The 202x group carries higher output current than the 200x group. Same channel counts, different drive capability.

And the EL2032 adds per-channel diagnostics. On a machine where a blown output needs identifying quickly, that is why it was specified.

Analogue input, EL3xxx

The largest family by a wide margin, and the middle digits carry the signal type.

Single-ended and differential are not interchangeable

The distinction that matters most in this family.

If a signal was noisy and someone specified a differential terminal, a single-ended one brings the problem straight back.

Same distinction as AI810 against AI820 on our ABB S800 page. It runs through every brand and it is worth checking before substituting.

Temperature terminals are type-specific

An RTD terminal will not read a thermocouple and a thermocouple terminal will not read an RTD. They are different measurement principles.

Within each, the terminal is configured for the sensor type in software. So an EL3202 covers Pt100 and similar; the sensor type is a setting rather than a part number.

Oversampling terminals do something different

The EL37xx group samples many times per bus cycle rather than once.

So they capture waveform detail a standard analogue input cannot see, for vibration analysis, power quality or fast process events.

A standard EL30xx is not a substitute. It will read the same signal and miss everything the oversampling terminal was fitted for.

Analogue output, EL4xxx

Same structure. The last digit is the channel count, and the middle digits carry the signal range and whether the output is voltage or current.

Voltage and current outputs are different terminals. A 0 to 10 V terminal cannot drive a 4 to 20 mA loop.

Position measurement, EL5xxx

The encoder interface decides the terminal. An SSI absolute encoder needs an EL5001; an incremental encoder needs an EL5101. They are not alternatives.

See our SICK encoder page for the difference between the two encoder types.

Communication, EL6xxx

These let an EtherCAT station talk to devices on another protocol. A weighing indicator on RS232, a legacy PROFIBUS drive, a CANopen valve island.

EL6001 and EL6021 are one character apart and are different electrical standards. RS232 is point to point and short; RS485 is multidrop and long. Check the device before ordering.

System terminals, EL9xxx

The parts that make a station work and get left off quotes.

The E-bus current budget in detail

The most useful engineering point on this page.

Beckhoff states the coupler supplies the connected terminals with the necessary E-bus current for communication, and that the EK1100 can supply a maximum of 5 V at 2 A.

When more is needed, power feed terminals such as the EL9410 must be integrated.

What consumes it

A station of digital terminals will rarely trouble the budget. A station of analogue and communication terminals can exceed it well before the rail is full.

The symptom is misleading

This is why it matters commercially.

Exceeding the E-bus current does not produce a clear error. Terminals toward the far end of the station behave erratically, drop off the bus intermittently, or fail to be recognised.

That looks exactly like a faulty terminal, and replacing it changes nothing.

So if a station has recently been extended and the last few terminals are misbehaving, check the current budget before ordering a replacement. The fix is an EL9410, not a new terminal.

Tell us what you are adding and to what and we will flag it.

The end terminal

Every station needs an EL9011 bus end terminal. Beckhoff's own description of a station is a coupler, any number of terminals, and a bus end terminal.

It costs very little and it is not optional.

When extending a station, the end terminal comes off, the new terminals go on, and it goes back on the end. If a station has been extended and nobody refitted it, that is worth checking.

Terminal order matters

An operational point that has no equivalent on most I/O systems.

EtherCAT Terminals carry no user configuration. The station is described in the TwinCAT project and terminals are addressed by their position on the rail.

The first point is the good news, and it makes Beckhoff spares unusually easy. A shelf terminal is a working terminal.

The second is the trap. If several terminals come off during a rebuild, they must go back in the same order.

ES terminals and pluggable wiring

An ES terminal is the EL equivalent with a pluggable wiring level. The field wiring stays in the connector when the terminal is removed.

Examples include ES2008 alongside EL2008.

On a machine that is stripped regularly, or where terminals are swapped for fault finding, that saves real time. On a fixed panel it is unnecessary cost.

They are not interchangeable as parts, because the wiring arrangement differs. An EL cannot take an ES connector.

What to send us

The full part number. The function and channel count are in it.

Whether the station is EtherCAT or K-bus. Check the coupler at the head of the rail.

What you are adding and to what, for the current budget.

Whether you need the end terminal.

A photo of the rail. Beckhoff labels the front clearly and one photo usually identifies a whole station.

What we can supply

Current production. The EL and ES ranges across all functions, EK couplers, EL9011 end terminals, EL9410 power feed terminals and accessories. Quoted with a delivered lead time.

Whole stations. Send the I/O count and we will quote the coupler, terminals, power feed and end terminal as a set.

Discontinued. Earlier EL variants and the KL Bus Terminal range. Surplus and tested used.

Beckhoff spares are easy to hold

Worth stating because it is unusual.

Because terminals carry no configuration, a spare is genuinely a spare. No programming, no settings, no matched pairs. It goes in and works.

So a sensible holding is one of each terminal type you run, plus an end terminal and a coupler. On a site with several stations that covers all of them.

We buy Beckhoff

EtherCAT Terminals resell readily because they are self-identifying and carry no configuration. If you are stripping a machine, they are worth considerably more than scrap.

Keep the coupler with its terminals. See Sell To Us.

Related

Beckhoff overview.

For distributed I/O from other brands see Siemens ET 200SP, Allen-Bradley FLEX and POINT I/O, Phoenix Contact Axioline and ABB S800.

Send us your part numbers

One terminal or a full rail. If the far end of a recently extended station is misbehaving, ask about the E-bus current before ordering a replacement. Quotes in NZD including GST.

Request a quote

Industech is an independent supplier of new, surplus and used industrial automation equipment. We are not an authorised distributor of, approved by, sanctioned by, or affiliated with Beckhoff Automation. Beckhoff, TwinCAT and EtherCAT are trademarks of Beckhoff Automation. All trademarks, brand names and part numbers are the property of their respective owners and are used here for identification purposes only.