PLC I/O Terminals

Showing 1 - 24 of 1104 products

Beckhoff EK1100 Beckhoff

$239.37

In stock, 25 units

EtherCAT Coupler

Beckhoff EL2809 Beckhoff

$151.94

In stock, 20 units

EtherCAT Terminal, 16-channel digital output, 24 V DC, 0.5 A

Beckhoff EL1809 Beckhoff

$170.63

In stock, 24 units

EtherCAT Terminal, 16-channel digital input, 24 V DC, 3 ms

Beckhoff EL9410 Beckhoff

$170.63

Only 10 units left

Power supply terminal for E-bus, with diagnostics

Beckhoff EL2008 Beckhoff

$150.00

In stock, 16 units

EtherCAT Terminal, 8-channel digital output, 24 V DC, 0.5 A

Beckhoff EK1101 Beckhoff

$411.26

In stock, 14 units

EtherCAT Coupler with ID switch

Beckhoff EL2904 Beckhoff

$406.67

In stock, 28 units

EtherCAT Terminal, 4-channel digital output, 24 V DC, 0.5 A, TwinSAFE

Beckhoff C9900-U330 Beckhoff

$502.92

In stock, 25 units

Battery pack

Beckhoff EL1008 Beckhoff

$147.71

In stock, 18 units

EtherCAT Terminal, 8-channel digital input, 24 V DC, 3 ms

Beckhoff EL3318 Beckhoff

$502.92

In stock, 20 units

EtherCAT Terminal, 8-channel analog input, temperature, thermocouple, 16 bit

Beckhoff CU8800-0010 Beckhoff

$663.33

In stock, 22 units

USB-Extender-Tx

Beckhoff EL1904 Beckhoff

$388.34

In stock, 13 units

EtherCAT Terminal, 4-channel digital input, 24 V DC, TwinSAFE

Beckhoff EL3104 Beckhoff

$709.17

In stock, 11 units

EtherCAT Terminal, 4-channel analog input, voltage, ±10 V, 16 bit, differential

Beckhoff EL1859 Beckhoff

$239.37

In stock, 18 units

EtherCAT Terminal, 8-channel digital input + 8-channel digital output, 24 V DC, 3 ms, 0.5 A

Beckhoff EL2004 Beckhoff

$159.17

In stock, 15 units

EtherCAT Terminal, 4-channel digital output, 24 V DC, 0.5 A

Beckhoff EL5101 Beckhoff

$457.08

In stock, 14 units

EtherCAT Terminal, 1-channel encoder interface, incremental, 5 V DC (DIFF RS422, TTL), 1 MHz

Beckhoff KL3054 Beckhoff

$342.50

In stock, 25 units

Bus Terminal, 4-channel analog input, current, 4…20 mA, 12 bit, single-ended

Beckhoff EL2502 Beckhoff

$594.59

In stock, 18 units

EtherCAT Terminal, 2-channel PWM output, 24 V DC, 0.5 A

Beckhoff KL4032 Beckhoff

$342.50

Only 6 units left

Bus Terminal, 2-channel analog output, voltage, ±10 V, 12 bit, differential

Beckhoff EP3184-0002 Beckhoff

$769.47

Only 7 units left

PLC Direct is not an authorized distributor. We offer a broad range of in-stock products with minimal lead time.

Beckhoff EL7041 Beckhoff

$502.92

In stock, 26 units

EtherCAT Terminal, 1-channel motion interface, stepper motor, 48 V DC, 5 A, with incremental encoder

Beckhoff EP1008-0001 Beckhoff

$411.26

In stock, 16 units

EtherCAT Box, 8-channel digital input, 24 V DC, 3 ms, M8

Beckhoff EL3064 Beckhoff

$388.34

In stock, 20 units

EtherCAT Terminal, 4-channel analog input, voltage, 0…10 V, 12 bit, single-ended

Beckhoff KL4004 Beckhoff

$272.57

Only 7 units left

PLC Direct is not an authorized distributor. We offer a broad range of in-stock products with minimal lead time.

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PLC I/O terminals are modular signal interface components that connect programmable logic controllers to field devices, including sensors, actuators, switches, and drives, handling digital and analog signal conversion at the edge of the control system. PLC Direct supplies PLC I/O terminals as an independent supplier, carrying surplus sealed, refurbished, and used hardware for maintenance and replacement in installed automation systems.

Where Are PLC I/O Terminals Used in Industrial Environments?

PLC I/O terminals are used wherever a PLC-based control system must interface with field-level signals across a machine or process, from individual digital inputs and outputs to analog measurement and control channels. These components are installed in control panels, field cabinets, and distributed I/O stations throughout manufacturing and process facilities.

Facilities and operations that depend on PLC I/O terminals include:

Discrete manufacturing plants distributing I/O across machine control panels and field junction boxes connected to a central controller over EtherCAT or PROFIBUS.
Packaging and material handling operations using modular I/O terminals to handle high channel-count discrete signal requirements across conveyor and sorting systems.
Automotive assembly facilities with distributed I/O terminal racks positioned at each workstation along the production line.
Water and wastewater treatment plants connecting pump station sensors and actuators to remote I/O terminal nodes across distributed control architectures.
Chemical and process industry facilities managing analog input and output channels for flow, pressure, temperature, and level instrumentation at field cabinets.

Replacement PLC I/O terminals are among the most routinely sourced automation components, as individual terminal failures in high-cycle applications are a common maintenance event.

Which Brands of PLC I/O Terminals Does PLC Direct Stock?

PLC Direct stocks PLC I/O terminals across the major modular I/O platforms deployed in installed automation systems worldwide.

Beckhoff EtherCAT Terminals (ELxxxx series) and Bus Terminals (KLxxxx series): Digital input, digital output, analog, and TwinSAFE-rated EtherCAT terminals across the EL series, alongside KL series Bus Terminals for fieldbus-neutral I/O installations, confirmed across multiple variants including EL1809, EL2622, EL1904, and EL2904.
Siemens SIMATIC ET 200SP I/O modules: Distributed I/O modules for the ET 200SP station, covering digital and analog signal types and interfacing with PROFINET and PROFIBUS networks via IM 155-6 interface modules confirmed in stock.
Omron CJ Series I/O modules: CJ1W-ID211 digital input, CJ1W-OC211 digital output, and CJ1W-MAD42 analog I/O modules for CJ Series PLC systems, providing modular signal expansion within installed Omron control architectures.
ABB S500 I/O modules: DA501 and DA502 digital/analog combination modules and TU515/TU516 terminal units for AC500-based distributed I/O installations, supporting digital and analog signal handling across multiple channel configurations.

PLC Direct carries PLC I/O terminals as surplus sealed, refurbished, and used hardware, giving maintenance teams options across condition grades and budget requirements.

What Should You Know Before Ordering PLC I/O Terminals?

Hardware condition options: PLC Direct supplies PLC I/O terminals in surplus sealed, refurbished, and used condition. Surplus sealed units are factory-sealed stock that has not been previously installed; refurbished terminals have been inspected and tested to confirm operational functionality; used hardware is sourced from decommissioned systems and suits facilities managing lifecycle replacements under budget constraints.

Compatibility and part identification: PLC I/O terminals are platform-specific and must be matched to the correct coupler, bus controller, or interface module for the installed system. Beckhoff EL series EtherCAT terminals require an EtherCAT coupler or compatible CX controller; Siemens ET 200SP modules require an IM 155-6 interface module matched to the network protocol in use. Confirm the terminal part number, signal type, channel count, and coupler compatibility from the installed system's hardware documentation before ordering.

Warranty: All PLC I/O terminal hardware purchased from PLC Direct carries a standard 1-year PLC Direct warranty covering defects and functionality, applicable to surplus sealed, refurbished, and used products.

PLC Direct supplies PLC I/O terminal hardware for replacement and maintenance purposes and does not provide system design, programming, or integration services.

Frequently Asked Questions

Local I/O terminals are mounted directly in the PLC rack and communicate with the CPU over the backplane bus, offering the lowest latency and simplest wiring for signals close to the controller. Distributed I/O terminals are installed in remote field cabinets and communicate with the controller over a fieldbus or industrial Ethernet network such as EtherCAT, PROFIBUS, or EtherNet/IP, reducing long cable runs across large facilities or machines.

EtherCAT terminals process I/O data in a single network frame that passes through each terminal in sequence, achieving sub-millisecond cycle times without a dedicated fieldbus controller at each node. This architecture allows large numbers of terminals to be added to a station without adding network overhead, making EtherCAT terminal systems particularly suited to high-channel-count and motion-critical applications.

Modular I/O terminal ranges typically cover 24 VDC digital input and output in various channel counts, analog input and output for 4-20 mA and 0-10 V signals, thermocouple and RTD temperature measurement inputs, pulse and encoder inputs for motion feedback, and safety-rated digital I/O for SIL-rated applications. The specific signal types available depend on the platform, with Beckhoff EL series and Siemens ET 200SP both offering broad signal coverage across these categories.

On platforms that support hot-swap capability, individual terminals can be replaced while the station remains powered and the network stays active, with the controller detecting the module change and resuming communication after reinsertion. Beckhoff EL series terminals and Siemens ET 200SP modules with multi-hot-swap support both offer this capability, though the specific behavior depends on the interface module and controller configuration in the installed system.

Most PLC I/O terminals have per-channel and module-level status LEDs that indicate signal state and fault conditions, and the controller's diagnostic buffer will typically log the specific module address and fault type when a terminal fails or goes offline. Cross-referencing the module address in the hardware configuration with the physical terminal position in the cabinet yields the part number needed to source a replacement.