Our control system: SCADA + PLC for ETO sterilization equipment


As expert in ETO sterilization process, we understand the importance of the process safety. For this reason, the safety is a priority for us, and it leaded us to develop a specific control system for the industrial ethylene oxide sterilizers.

This ethylene oxide sterilization process requires a high level of safety due to the dangerousness of the gas under uncontrolled situations (it is explosive, flammable and toxic). Therefore, it is vital to have an optimal and reliable process, an adequate personnel training and a state-of-the-art equipment to guarantee the safety.


Our comprehensive control system "The ONYX control system"

The ONYX control system is composed of a safety PLC and a SCADA, quite common for an ethylene oxide sterilization equipment. Together, they ensure the process safety as well as the personnel and the installation.

The PLC is the “brain” of the equipment, where all the functions are handled to perform the process operations. RSD uses a high-quality safety PLC (Siemens/Allen Bradley) and SIL certified as per IEC 61508.

On the other hand, the SCADA purpose is to analyze and communique all the PLC inputs and outputs. In that way, the operators can control the process parameters (humidity, gas concentration, pressure, …) under safe conditions. In addition, our SCADA includes alarms, synoptics, recipes and other screens that are necessary to handle the Ethylene Oxide sterilization process.

The quality of the control system is an important aspect to take into account, it should bring to the customer optimal results in terms of the safety, productivity and efficacy. It is significant not to skimp this feature, as the control system affects to the sterilization process and can lead to negative consequences.


The advantages of ONYX control system

As we have indicated previously, RSD has developed its own control system including a SCADA technology operating with a safety PLC. Our application is based on the HAZOP analysis and SIL definition for each project, always meeting the 21 CFR Part 11.



  • RSD SCADA presentation GRAPHApplication development taking into account customer’s needs and requirements, fulfilling the GAMP 5 recommendations.
  • Use of database (SQL), protected by passwords.
  • Installation interlocks are handled from the control system.
  • Possibility to work with audit trail.
  • Several levels of users are proposed: operator, supervisor, director, maintenance, administrator and calibration), each one customized with access to some actions according to the user level.
  • Creation of flexible recipes. Possibility to configure the sterilization cycle thanks to several parameters.
  • The inflammable diagram is automatically calculated.
  • Screen for calibration operations.
  • Possibility to switch to manual or automatic modes.
  • Automatic generation of final reports.
  • Several screens are available like synoptics, graphs, alarms, …

 Our PLC:

  • Safety PLC, Siemens or Allen Bradley brand.
  • Certification according to SIL normative (IEC 61508) for a higher reliability.
  • Safe modules for critical inputs and outputs, and common functions for the rest.

We propose a high-quality solution that integrates advanced technologies.


The validation protocols

To ensure that the operations of the ETO sterilization equipment are safe and reliable, it is essential to validate the control system according to quality protocols.

In such a case, RSD generates and executes strict protocols, which are the following:

  • SDS (Software and Design Specifications).
  • SMDS (Software Module Design Specifications).
  • SMTS (Software Module Test Specifications).

The purpose of these software validation protocols is to ensure that the customer acquires a safe, efficient and reliable control system to make sure that the process and the personnel safety are optimum. Also, it allows the customer to analyze, control and execute the ETO sterilization process with user friendly screens, to make easier the process control. 


Our standard control solution has been developed to suit to most of the customer’s requirements while they fulfil all the applicable standards and regulations. However, tailor-made applications can be developed for any special need.

RSD control system is implanted in our industrial ETO sterilizers, dedicated to pharmaceutical and Medical Devices companies. We offer comprehensive ETO sterilization solutions for turnkey projects.


Contact us for more information.



EtO sterilizers ONYX control system