Bill's Deep Dive on Opto 22 EPIC System Programmable Edge Controller

  • September 25, 2018
  • Feature
Bill's Deep Dive on Opto 22 EPIC System Programmable Edge Controller
Bill's Deep Dive on Opto 22 EPIC System Programmable Edge Controller

By Bill Lydon, Editor,

Today we take another dive into the world of new technologies in today’s automation ecosystem. For this article, I had opportunity to examine Opto 22’s groov EPIC product at the 22nd annual ARC Industry Forum in February.  The company refers to the groov EPIC as an Edge Programmable Industrial Controller.  Having been around since 1974, Opto 22 is a familiar name to automation engineers like myself who have applied their products beforeAs many other automation engineers, I have known Opto 22 for many years applying their products.  Founded by engineers who designed and manufactured solid-state relays the became a de facto standard in many control automation applications, I was intrigued by their new controller.   I spoke with Opto 22’s Vice President Benson Hougland, a 23-year company veteran, about the new product.

 groov EPIC (Edge Programmable Industrial Controller)


Question: The new EPIC System is quite a bold step. What motivated Opto 22 to develop this product?

Hougland: Opto 22 has a long history in the automation and controls industry of challenging the status quo by bringing products to market that incorporate the latest technological advancements, largely driven from information technology.

In the 1980s, we were the first to challenge the dominance of PLCs by introducing PC-based control. We followed that in the 1990s with the commercial introduction of pure Ethernet-based I/O, even before an industrial Ethernet protocol existed (so we developed one and made it publicly available for use by anyone).

In the 2000s, we marshalled the introduction of machine-to-machine communications, partnering with the world’s largest global cellular communications provider. And now, we’ve introduced an edge programmable industrial controller based on open-source technologies (Linux), industry standard microprocessors (ARM), industrial solid-state drives, and world-class software.

But what truly motivated Opto 22 to build groov EPIC was addressing the automation problems our industry faces every day: security, access to data, connectivity, programming limitations, and implementation issues largely attributed to challenges with IT personnel. We’ve also noticed that a new breed of engineers and developers is coming into the automation space. They expect openness, software options, and mobility—all baked in, not bolted on—and we are driven to help them succeed.


Question: The EPIC controller looks like just another PLC with a processor and slot I/O, what distinguishes it from a PLC?

Hougland: At a casual glance, groov EPIC appears similar to a PLC as EPIC is also chassis-based. However, a second glance reveals a high-resolution, touchscreen display on the face. And a slightly deeper look shows that this display offers a full management interface to the controller, its I/O, and all software running locally on the device.

But mere appearances don’t reveal the true power of EPIC. The value in this system lies in what you cannot see: a broad and useful array of software capabilities, including a mobile and web-based HMI server; OPC UA drivers for connection to standard, popular PLCs; MQTT publish/subscribe communications with Sparkplug payload; a real-time control engine; and an IBM-developed but now open source data flow editor and runtime called Node-RED.

groov EPIC is also the first full-featured industrial controller of its kind with Inductive Automation’s Ignition Edge Onboard for connectivity and communications.

groov EPIC Architecture


Question: What is the range of input and output types?

Hougland: The groov EPIC system offers a broad array of input and output types in channel-to-channel isolated configurations, or non-isolated versions. All modules provide control-to-field side optical isolation. 

The digital/discrete inputs and outputs offer ranges from 2 V to 280 V in both dc and ac configurations, with 12 to 24 channels per module. Mechanical relay outputs are also available, as are lower cost “simple” versions that offer read/write on/off capability only.

Analog I/O modules include voltage and current inputs with software selectable ranges, and thermocouple/millivolt inputs with software selectable thermocouple types and millivolt ranges. Analog inputs offer 20 bits of resolution at 0.1% accuracy.

Analog voltage and current outputs are handled by a single output module, software configurable for seven voltage and current ranges, which also provides an isolated loop supply for current outputs. Analog I/O modules have 8 to 24 channels, and each channel is individually configurable.

All I/O module data is accessible by a built-in RESTful API for access by any authorized software application, including user-developed software running on the groov EPIC controller.

Easy wiring access



Question: How are applications programmed?

Hougland: The “P” in EPIC is for programmability, and options include Opto 22’s flowchart-based PAC Control with scripting for any control application; future support for 3S Software’s CODESYS IEC-61131 programming environment; and available shell access to the controller’s operating and file system for uploading any user application developed with programming languages and runtimes such as C, C++, Java, node.js, Python and more.


Question: Is there support for OPC UA client and server?

Hougland: groov EPIC offers multiple OPC UA client applications, such as the included groov View application, a mobile and web-based development environment and server for building and viewing scalable, full-function HMI screens; support for Inductive Automation’s Ignition Edge Panel HMI; and Node-RED.

groov EPIC also provides an OPC-UA server and drivers to popular PLCs from Allen-Bradley/Rockwell Automation, Siemens S7-series, Modbus/TCP and RTU over TCP, Omron, DNP3, Opto 22’s SNAP PACs and groov EPICs and more.


Question: Does it support EtherNet/IP (CIP), Profibus, Profinet, EtherCAT protocols at the controller level?

Hougland: Support for alternative Ethernet-based industrial automation protocols is slated for a future release. In the meantime, our SNAP PAC family of Ethernet I/O provides EtherNet/IP and Modbus/TCP support built-in, and SNAP is fully compatible with the new groov EPIC system.


Question: Can an EPIC controller serve as a gateway for EtherNet/IP (CIP), Profibus, Profinet, EtherCAT protocols?

Hougland: The groov EPIC serves as a gateway to PLC protocols like EtherNet/IP through the Ignition Edge OPC UA server and assorted included drivers, and through freely available integration kits for the PAC Control programming environment.


Question: What is the flowchart-based programming referenced in the EPIC literature?

Hougland: The flowchart-based programming software included in groov EPIC is Opto 22’s PAC Control, which has a 28-year track record of control software implementations worldwide. PAC Control has a long history of providing flowchart and script-based programming methods to address nearly any automation application.

PAC Control uses a comprehensive, plain-English command set with 450+ commands for analog process and digital sequential control, complex math, conditional branching, string handling, serial device control, PID loop control, etc. PAC Control also includes subroutines, a graphical debugger and a graphical PID tuner.

Programming options include Flowchart, IEC 6-1131, C, C++, Java, node.js, Python and more.


Question: How does EPIC support Node-RED? 

Hougland: groov EPIC includes the IBM-developed, open-source Node-RED data flow editor and runtime, ideal for creating and deploying industrial IoT applications in minutes without programming. The Node-RED implementation in groov EPIC adds a secure user authentication interface to the editor, includes Opto 22 nodes for communications with control engine data and groov View projects, and offers project management tools to back up and restore flows and credentials, plus troubleshooting options. 


Question: Does EPIC have an embedded Node-RED run-time engine in the controller?

Hougland: groov EPIC does embed the node.js runtime engine directly on the controller. 


Question: How does EPIC support Industry 4.0 and the Internet of Things applications?

Hougland: The edge capabilities of the groov EPIC controller make it uniquely suited for industry 4.0 and Industrial Internet of Things (IIoT) applications. The software packages embedded on the controller facilitate the IIoT and Industry 4.0 tasks engineers are trying to do. Embedded software includes Node-RED for data flow, API interaction, and cloud-based applications; Ignition Edge for edge processing of controls data, PLC data communications; and publish/subscribe architectures with MQTT and Sparkplug; groov View for data visualization from anywhere; and PAC Control for embedded real-time control and I/O.


Question: Does EPIC have an embedded historian?

groov EPIC has several methods for historizing data directly on the controller, depending upon the needs of the application. groov View can be used to create real-time and historical trends and trend files, Ignition Edge can be used to historize locally, and Node-RED can be used to archive data locally.


Question: How does groov EPIC address security and access to data?

groov EPIC provides several layers of security and access control.

At a physical level, the groov EPIC processor has two independent Ethernet network interfaces. One can be used for the control network, and the other for a company network with access to the internet. This built-in method of keeping those networks separate helps protect the control network from outside contact. The firewall within the processor can also be configured to disable network interfaces or assign them to only use specific protocols.

Access to information on the EPIC processor's integrated high-resolution touchscreen requires username/password authentication, and user security levels determine what configuration information and data an individual operator can see and change. Authorized users can also access this information through a computer or mobile device; again, passwords are required. All data communications between the EPIC processor and PCs or mobile devices is encrypted using TLS/SSL—the same encryption used in the financial industry.

The groov EPIC processor comes with several software programs for real-time control, connectivity, and IIoT data sharing—PAC Control, Node-RED, Ignition Edge, groov View HMI—plus an API (application program interface) to data in the processor. The EPIC system administrator sets user levels and permissions and limits the data each user (human or software) can access. Commands within the PAC Control software determine which data to make public and set read-only or read-write access to data elements.

Of course, these layers of security and access control in the groov EPIC system are part of an overall security effort required by end users to keep their data and systems safe.


Question: What industry applications is EPIC targeted to support?  (Discrete, Process, SCADA, ??)

groov EPIC is a hybrid controller ideal for continuous process control, batch, discrete automation, SCADA, communications, PID loop control, sequencing, recipes, and much more.


Question: Is EPIC robust enough to support applications such as packaging lines and other high-speed automation and control?

groov EPIC is a hybrid controller designed to perform as required for packaging lines, and other machine automation applications.

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