A Wider Variety of Signal Options Within a Single I/O Module

Beckhoff is a global supplier of PC-based controls, control cabinet devices, vision, and motion control systems. Their flagship product is an industrial PC (IPC) which integrates with their product line using Beckhoff’s software, TwinCAT. Beckhoff’s input/output (I/O) systems consist of expandable modules, field-mountable I/O blocks, and network interface components. Recently, Beckhoff added to their expandable panel I/O modules with a 12-channel multi-interface terminal. 

 

Beckhoff's EL8601-8411 12-channel, multi-interface EtherCAT Terminal. Image used courtesy of Beckhoff

 

Expandable I/O 

Most control systems or automated equipment have different kinds of input sensors or output devices that are required to interact with the physical surrounding space. A typical control system consists of a CPU and a field I/O module that is expandable to a maximum number of input or output terminals. Most systems also have I/O modules that can be added directly to a PLC. Each PLC or remote I/O block typically has digital inputs or outputs, and sometimes the channels are configurable between the two. Some terminals can also handle analog signals or encoders, once again, with various configurable options.

Beckhoff's EL8601-8411 is special. This module contains twelve channels that can be configured for digital, analog, pulse width modulation (PWM), counter, or encoder, all within a single 12 mm wide module. This level of configurable channels is typically only found with IO-Link. The module can be added to the CX7000 embedded PC, making for a very compact and powerful micro IPC.

 

The EL8601-8411 has twelve channels that can be configured for digital, analog, PWM, counter, or encoder, all within one, 12 mm wide module. Image used courtesy of Beckhoff

 

Beckhoff's I/O Module

This EL8601-8411 is a configurable input and output module, which means that some channels can be configured and some cannot. The channels are divided up as follows:

• eight digital input channels, one of which can be configured as an “A/B” encoder or as an up/down counter
• two digital outputs that can be configured as PWM output with a frequency range of 20 Hz to 25 kHz
• one analog input and one analog output, both are configurable for current (4 -20 mA) or voltage (0 - 10 VDC) measurement

The configuration process takes place using Beckhoff's TwinCAT programming software. Once the device is added to the hardware configuration, the device properties can be used to set the function of the configurable ports

 

Building Configurable Controllers

When designing a control system, you always need to know how many inputs and how many outputs, and typically during integration, you need to add more modules or add special function modules. With configurable I/O modules, you can remove some of the guesswork during the design phase or use them as insurance when the equipment hits the floor.

Using configurable I/O modules can also save space in the electrical cabinet—if your system is small and only requires a few digital inputs, digital outputs, and some analog inputs, you might get away with only two expansion modules instead of three.

Specialty modules like encoder modules, counter modules, or even output modules with PWM functionally can be hard to come by as they are not used as much as the digital input or output modules. By selecting configurable modules with special features, you ensure a flexible, robust control system.