Process Control And Data Acquisition In Pharmaceuticals Plant

ControlNet

Discuss about the Process Control and Data Acquisition in Pharmaceuticals Plant.

Pharmaceutical industries are among the largest and fastest growing sectors in the world today. Some of the clear characters of this area are competition, strict regulation due to critical products they produce as well as low durability of their products. Some of the key factors given keen attention here include quality, safety, flexibility and efficiency. Use of process control systems such as ControlNet and Safety NET p networks can help achieve this. 

It supports controller to controller interlocking and real-time control of I/O, devices, and valves as well as control networking for process applications. ControlNet offered by some companies such as Allen-Bradley have built-in control interface or have the ability to connect through optimal communication interface module which improves real-time and throughput application support (ODVA, 2016).

When designing network ControlNet media and connection devices offer flexibility. ControlNet coax cable, a low-loss is an RG-6 quad shield that immunity to electromagnetic interference to allow installations in hazardous locations. Allen-Bradley provides a variety of network media such as taps, connectors, terminators, repeaters and coax tools as well as fiber systems. The types of the network media chosen will depend on the process application type and the environment (Ba?ak, 2015).

Control NET is an example token passing control designed to offer reliable, high-speed transport monitoring and input, output (I/O) data.  It also provides non-time critical messaging data. I/O data is assigned the highest priority such that other data such as parameter upload and downloads do not interfere with the control and I/O data transport.

ControlNet is classified as a deterministic network since it uses token rotation time to characterize maximum waiting time needed to send a message frame.

The token bus networks nodes are logically arranged to form a ring such that each node knows its previous and next node. This way it is possible to offer liner, multi-drop, tree-shaped or segmented topology (Lian, 2011).

The network node in possession of the token is allowed to transmit data frames till its allocated token time expires, or it runs of data packets. Then the token regenerated and sent to the next logical node in the network (ring). If the node that receives the token has nothing to send then it just passes the token to the next neighbor in the logical ring. Data frames do not collide since its only one node that is allowed to transmit data frames. This node is the one that is in possession of the token, others nodes need to wait for the token.

Operation

Token ring protocol offers assurances of maximum time between node network access and protocol with the capacity to regenerate the token if the node in possession of the token stops transmitting the data frames and does not release the token to the next neighbor in the ring.

Nodes are added dynamically to the ring and can also be removed from the ring on request.

As we have discussed above that token bus protocol is deterministic that guarantee throughput and high efficiency when there are high network loads. Nodes can be added dynamically during network operation and also remove the nodes that have failed in the ring or those which are no longer needed. Removing failed nodes is a major score over token ring protocols where nodes are statically added or removed (Healy, 2015).

Control net uses the implicit token passing mechanism which allocates mac id to every node in the ring to prevent data frames collision. Only the nodes with the token are allowed to send data frames. Every node sets the implicit token register to “mac id +1”. When the mac id of the node is equal to the implicit token register, it now transmits the frames. To prevent collisions, all nodes have similar value in implicit token registers.

ControlNet support time critical through the provision of scheduled segments as well as and non-time critical messages through unscheduled segments in every NUT (Network update time) cycle. The NUT is divided into scheduled, unscheduled and guard band sections. Scheduled section of NUT allows scheduled data transmission while un-scheduled section allows each node to transmit noon time critical data using round robin protocol. During guard band time all nodes stop transmission thus allowing the moderator node (node with lowest mac id) to transmit maintenance message. This message synchronizes timers and publishes critical link parameters like node time, S, U, NUT and many more others.

Token bus protocol is only efficient at high network loads but at low channels traffics its performance is poor compared to contention protocols. Token bus protocol uses a huge percentage of network time to pass the token between the nodes when the data traffic is light since there are many nodes in a single local ring (Zhang, 2012).

According to IEC series standards, safety NET p is defined as Type 22 and CP 18. It is a standard for Ethernet-based field bus communication in automated technology.

Advantages of Using ControlNet

Safety NET p communication model describes communication system, application layer, and transport layer. Application layer represents the communication system’s interface. The functions of the device safety NET p are accessed through the interface; thus it is the interaction medium between the user and the system. It uses two transport mechanism namely: RTFL and RTFN.

It automates data and safety-related data simultaneous transmission with vertical and horizontal integration. To design a network topology, safety NET p offers a range of infrastructure components such as switches, cables, and connectors. Safety NET p implements the network infrastructure.  Network topologies such as star and tree which adapt to pharmaceutical plant support which can significantly increase performance. To do these switches such as PSS net can be used to adjust the topology flexibility to pharmaceutical plant layout. It can support star, tree and ring topologies. PSS net switch has fiber optics media which allow expansion of the network without limitations.  Other installation media used include safety p connectors and cables for fast and straightforward installation. These materials are available at some companies such as Safety Network International (Sankaran, 2016).

Safety NET p offer effective detection and management of the network structure which supports the connection of service devices whenever required as well as mobile apps support. Its communication structure uses a distributed PLC which facilitates peer to peer data transmission that results in distributed data-processing. Pharmaceutical plants have a flexible and modular structure that describe their dimensions, plan, and commissioning.  Safety NET p has proxies that offer communication platform for existing field bus installation to communicate with other plant sections. It also can access data from various field buses thus optimizing the plant protection (Safety-network.org, 2016).

Safety NET p has a real-time capability to support safety functions as well as real-time functions that enable flexible and cheap procedure by use of generic Ethernet interface or RTFL and protocol chip of safety NET p. These support a real time scan of about 62.5 seconds.

Standard Ethernet, on which safety NET p network depends on, has been tried and tested for several years in office communication. On top of that is meets the stringent specifications of the pharmaceutical application as it can support the transfer of data from conventional control process, transfer of safety-related data and offer real-time communication in a high dynamic form as well as synchronized applications thus allowing one network connection for all control data and machinery  (Synchronics.co.in, 2016).

Disadvantages of Using ControlNet

Safety NET p also can offer new horizons for pharmaceutical plant control technology. It maintains an interior view to monitor intelligence while at the same time providing decentralized control information to field level. The plant is logically divided into functional machine modules.

 To fast sensor actuator loops it is important to connect manufacturing cells in the motion control areas. When safety NET p is used, it offers an extremely high real-time capability. The safety signals encountered in the factory automation are transmitted using the same medium. The cells are interconnected through RTFN (Efficient Real-Time Industrial Ethernet Links, 2016).

Conclusions

It is true that open, safe and deterministic real-time Ethernet that meets all user requirements. The real-time performance is approximately 20 times faster (scan times 62.5 s) than most of the industrial networks. Safety NET p is excellent for transport medium when the when secure communication is integrated from the start. Any Ethernet traffic such as data traffic from other industrial Ethernet versions, laptop or video is supported. Its flexibility allows the plant to have a linear, tree and star structure. It also has unrivaled capacity to charge structures and subscribers during operation

Control net is a state of the art Network which is a high-speed deterministic network suitable for time-critical application data. Most of the pharmaceutical plant have time critical data as they deal with products that are very critical and perishable. Data transmission here is paramount for healthy products manufacturing. It also offers real-time control and messaging services to p2p communication network while providing a combination of controller and I/O device capabilities using its high-speed link.

Control net offers deterministic real-time interlocking, peer to peer programming and messaging as well I/O bandwidth within the same link.

Control net is a state of the art Network which is a high-speed deterministic network suitable for time-critical application data. Most of the pharmaceutical plant have time critical data as they deal with products that are very critical and perishable. Data transmission here is paramount for healthy products manufacturing. It also offers real-time control and messaging services to p2p communication network while providing a combination of controller and I/O device capabilities using its high-speed link.

Control net offers deterministic real-time interlocking, peer to peer programming and messaging as well I/O bandwidth within the same link.

References

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Efficient Real-Time Industrial Ethernet Links. (2016). IJSR, 5(3), pp.1106-1109.

Ethercat.org. (2016). Ether CAT Technology Group | Safety. [Online] Available at:

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Healy, J., 2015. What Role do Safety Net Wage Adjustments Play in Alleviating Household Need?. Journal of Industrial Relations, 53(2), pp. 169-192.

Lian, F.-L., 2011. Performance Evaluation of control networks: ethernet, controlnet and devicenet , Michigan: University of Michigan.

ODVA. (2016). Control NET. [Online] Available at: https://www.odva.org/ [Accessed 27 Oct. 2016].

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Safety-network.org. (2016). Safety Network International e.V. - User organization.

[Online] Available at: https://www.safety-network.org/en/ [Accessed 27 Oct. 2016]. 

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Sankaran, S., 2016. SafetyNET p Protocol, New York: s.n.

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