How to select automation components for your pharma equipment

Automation in equipment is becoming the new standard and necessity  for every industry, including the pharmaceutical sector. It helps automate the machine operations, digitalize manual systems, reduces human involvement, and increases accuracy & productivity. It  also enables the automatic recording of critical variables and documentation, which is a key regulatory requirement.

Automation is implemented by using automation components. They are designed to perform different actions, such as measuring physical variables and detecting different machine positions. The combination of different automation components and programming logic, enables a designer to make a machine specific to pharma  industry requirements. 

Some Common Automation Components used in the pharma industry

Some common automation components include but are not limited to the following.

Proximity Sensor

These are components that can detect the presence or absence of an object, both metallic and non-metallic. They work by activating or deactivating internal electronic mechanisms. Typically, there are two types: capacitive and inductive. 

Capacitive sensors are used to detect non-metallic objects, while inductive sensors are used to detect metallic objects. 

Temperature Sensors

Temperature sensors are used to sense the temperature and convert into appropriate forms. Some temperature sensors are also fitted with signal conditioners that convert into the electrical signal. These signals are then transmitted to different components.

Pressure Sensors

They are used to sense pressure and generate equivalent electrical signals, which are then sent to the controller for controlling different applications. 

Another form of pressure sensor is called pressure switch. In contrast to converting into electrical signals, the switch is activated when a specific pressure is detected at the sensing point. 

Electric Motors

They convert electric energy into rotary form. Electrical energy energises the internal components, which creates a magnetic field. It then rotates the shaft inside the body. 

Valves & Pumps

Valves receive electrical signals to open or close, passing or stopping the passage of fluid through it 

A pump is used to transfer liquid or water from one equipment or area to another. They can be controlled by either start/stop mechanisms or by adjusting their speed.

Programmable Logic Controller - PLC

Controllers or Programmable Logic Controllers (PLCs) are the brains of automation systems. They receive input from various sensors, such as temperature and pressure, and based on the stored algorithm, they process these values. This, in turn controls the entire machine according to the process requirements.  

Human Machine Interface - HMI

HMIs are touch panels that can take inputs from humans by sensing their touch from the screen panel.  The input is then transmitted to the controller or PLC indicating different processes or product requirements. 

Engineers develop different functionalities of the screen in the form of graphical shapes, designs, and numerical numbers. Touching the respective shape on the screen activates that function, which is effectively translated and transmitted to the controller. 

Communication

They are used to establish communication between different automation components, such as PLC and HMI.

Power Supply

Power supplies provide power to automation components. They produce specific DC voltage, since most automation components require DC voltage to activate and operate.

Safety

They are electronic sensors that activate when a hazard is present. 

Some tips on selecting automation components for your applications

Although automation components are built-in by the machine manufacturer, and the machine manufacturer itself selects these components. However, there are some cases, when the machine buyer or user has to procure alternate components,  due to many reasons,  such as the original part or manufacturer may not be available. 

Let's see how we will select these components.

Proximity Sensor

Proximity sensors are used in pharmaceutical machines to detect the presence or absence of an object, such as packaging material, at the sealing station in blister packaging machines.

Some checklists when selecting proximity sensors include but are not limited to the following

· Object detection -  metallic or non-metallic

· Power supply - DC or AC

· Outer diameter

· Output type - NO or NC

· IP rating

The above parameters can be identified by studying the existing proximity sensor installed for a particular application using the data sheet

Temperature Sensor

Temperature sensors are used to measure the temperature level in various pharmaceutical machines, such as Autoclaves and Vessels. The measured value is then transmitted to the central controller for further processing. 

For selecting a temperature sensor, the following parameters must be checked. 

Sensor type 

Thermocouple or RTD. These two differ in working and output type. 

Output Type

Some temperature sensors also incorporate transmitters within their design. It converts the temperature value into an electrical signal, i.e. 4 - 20mA or 0 - 10V. 

On the other hand, some temperature sensors directly transmit the measured value to the controller, without converting into another forms

Measuring range

The measuring range refers to the total sensing span of a temperature sensor. Pharma equipment’s temperature range depends on the process and application. For example, the autoclave temperature range is lower, i.e., 100°C to 130°C, while for blister packaging machines, it ranges from 200°C to 250°C.

Number of Wires

RTD temperature sensors are available in two-, three-, and four-wire variations for enhanced accuracy and error reduction. 

Size

These parameters relate to the physical appearance of the sensor for installation purposes and include length, threads and connection type

Thermocouple types 

Thermocouple sensors come in various types, such as K-type and J-type. These types differ in ranges and their  output values.

Pressure Sensor

Pressure sensors are used to monitor pressure in various applications, such as autoclaves and steam systems.

When selecting a pressure sensor, consider the following key factors.

Application

In the pharmaceutical industry, different processes  and equipment utilize different  pressure applications. . Different sensor types are designed for  each pressure application and must be used appropriately. 

Some sensor types according to pressure applications include the following

· Absolute pressure - pressure levels of a container w.r.to complete vacuum condition

· Differential pressure - difference of pressure between two points

· Gauge - to manually indicate  pressure on a gauge

Range 

It is the working range of the pressure for a given process and must be selected with some tolerance levels to prevent sensor damage

Output Signal 

If the pressure sensor is electronic,  it is the output type from the sensor. Common type includes 4 - 20mA and 0 - 10V

Physical Dimension

It includes physical characteristics used to mount or install the sensor. Examples include thread, flange and flush.

Electric Motor

Electric motors are used to rotate the main cam or driver for the machine, which in turn operates different functions of the machine. The following factors are taken into consideration when selecting an electric motor.

· Voltage type: AC or DC. 

· Number of phases - single or three phase for AC motor

· Power and SpeedSpeed – these parameters are critical for specific application types. If the application requires a heavy load, a high-powered motor is used. Similarly, if the application involves high SpeedSpeed, the relevant motor model is selected.

Valves and Pumps

For valves, the following are parameters to be considered

· Type - butterfly, globe valve, throttling, ball valve

· Operating mechanism - if valves are automatically controlled, what are their operating voltages

· Fluid type - Steam, water or gas

· Flow rate - The capacity of the valve for flowing fluid through it

· Physical Characteristics - piping size and connection type

Programmable Logic Controller - PLC 

Programmable Logic Controllers (PLCs) are used to control the entire  machine according to user or application requirements. Some factors to consider when selecting a PLC include the following.

· Application requirements - what are your specific requirements, and what functions do you want to operate? Does the application require a large number of I/Os or a small number, and many others?

· Input / Output description - what are the types of inputs the PLC is capable of receiving, and the output type the PLC can generate. Common types include, Analogue and Digital

· Communication  – what communication protocol a PLC uses to  communicate with another components

· Power Supply - what power supply does PCC use to operate, i.e. DC or AC

Human Machine Interface - HMI

Some factors to consider when selecting HMI include the following.

· Size - it is the diagonal length of the touch panel and comes in different sizes. For complex applications, a large HMI is suitable, while for simple applications, a small HMI is appropriate.

· Communication ports - communication protocol to communicate with other automation components and  PLC

Power Supply

A power supply is used to power up automation components and is the name given to voltage-producing component 

When selecting a power supply, consider the following factors.

· Rating - it is the total capacity of the power supply to power all automation components, including voltage and current ratings. 

   · For current, it must be able to provide current ratings for all components and is determined by adding the current requirements of individual automation components.

   · For voltage, it must be able to provide voltage levels in the required range.

· Linear Or Switching - for industrial applications, Switching is preferred due to its higher efficiency.

· Physical dimensions - use a power supply that can fit into the intended space, such as an electrical panel

· Safety features - select a power supply that offers safety features to prevent damage. Examples include over-voltage,over -  current, and short-circuit protection.

· Line regulation - a power supply can maintain and stabilise its output in an event of  variations in input voltage.

· Voltage regulation - a power supply can maintain and stabilize the output voltage in times of fluctuations in the output load