Rockwell Automation Software/FactoryTalk Portal

The FactoryTalk Portal is a part of the FactoryTalk Integrated Production and Performance Suite. It enables manufacturers to merge their Web-based interfaces into single configurable and convenient launch point. In our manufacturing processes FactoryTalk Portal furnishes:

• Improved productivity through personalized and collaborative access to information, applications, processes, and people.

• Information where it needs to go and to the right people.

• Reduced Total Cost of Ownership (TCO) by providing a platform for manufacturing applications.

Services offered

FactoryTalk Portal server software presents core portal services like

1. Role-based access to applications and content
2. Search
3. Personalization
4. Security
5. Portlet development capabilities (the visible, active components in a portal page). 

Winpcap

Pcap i.e. packet capture consists of an application programming interface (API) for capturing network traffic. Unix-like systems implement pcap in the libpcap library whereas Windows uses a port of libpcap known as WinPcap. WinPcap is the packet capture and filtering engine of many open source and commercial network tools, including protocol analyzers, network monitors, network intrusion detection systems, sniffers, traffic generators and network testers. Popularly known tools include Wireshark, Nmap, Snort, ntop etc. WinPcap contains a driver that extends the operating system to provide low-level network access, and a library that is used to easily access the low-level network layers.

Sniffer

It is also known as a packet analyzer, network analyzer or protocol analyzer. It is a computer software or computer hardware which intercepts and logs traffic passing over a digital network or part of a network. As data streams flow across the network, the sniffer captures each packet and ultimately decodes and analyzes its content according to the appropriate RFC or other specifications. A packet sniffer is used to:

• Analyze network problems

• Detect network intrusion attempts

• Gain information for effecting a network intrusion

• Monitor network usage

• Gather and report network statistics

• Filter suspect content from network traffic

• Spy on other network users and collect sensitive information such as passwords

• Reverse engineer proprietary protocols used over the network

• Debug client/server communications

• Debug network protocol implementations 

REST Interaction, Protocol Servlets & Example

A REST interaction generally includes following elements:

• Operation— It belongs to a restricted, well-known set of operations—for example, in the HTTP protocol, the main operations are GET, POST, PUT, and DELETE. The operations are all known in advance hence no need arises to define interfaces for a RESTful protocol. In this regard, REST architecture is advantageous as compared to RPC architectures.
  
  
• URI— It identifies the resource that the operation acts on. For example, a HTTP GET operation acts on the URI by fetching data from the resource identified by the URI.
  
  
• Data (Optional)— It is required for operations that send data to the remote resource.
  

REST Protocol Servlets

The REST protocol is implemented by the following servlets running in a Web container:

• message servlet— It supports the sending and consuming of messages.
• queueBrowse servlet—It enables us to monitor the contents and view the current status of a particular queue. It is an effective and simple management tool.
  

RESTful Example

The World Wide Web is a major example of RESTful design and conforms to REST principles to a large extent. The Web consists of the Hypertext Transfer Protocol (HTTP), content types including the Hypertext Markup Language (HTML), and other Internet technologies such as the Domain Name System (DNS).

• HTML can include JavaScript and applets to support code on demand, and has implicit support for hyperlinks.
• HTTP has a uniform interface for accessing resources, which consists of URIs, methods, status codes, headers, and content distinguished by MIME type.

HVAC - Ventilation

Building ventilation

The process of bringing outside air into a building, circulating it, and later purging it to the environment is known as Building ventilation. The purpose behind ventilation is to provide adequate indoor air quality by diluting and removing contaminants from the indoor air. This can be achieved either by natural or mechanical means, or by a combination of both.

Natural ventilation

Natural ventilation is done by using air pressure differences existing between the inside of a building relative to the outside of it, across the building envelope. Natural forces such as wind and temperature create these air pressure differences. In naturally ventilated buildings air moves through windows, doors, vents and other openings built-in into the building design and via infiltration/exfiltration.

Mechanical ventilation

Mechanical ventilation is done by utilizing mechanical air handling systems which are commonly referred to as heating, ventilation, and air conditioning i.e. HVAC systems. Mechanical ventilation is more controllable and responsive as compared to natural ventilation in providing adequate indoor air quality hence employed in mainly commercial buildings. An HVAC system provides adequate indoor air quality by:

• Conditioning the air in the occupied space of a building

• Diluting and removing contaminants from indoor air through ventilation

• Providing proper building pressurization. 

Simple Network Management Protocol( SNMP) Part 2

 Basic Commands

Four basic SNMP commands used for monitoring and controlling managed devices include:

1. Read command: It is used by an NMS to monitor managed devices. The NMS examines different variables that are maintained by managed devices.
2. Write command: It is used by an NMS to control managed devices. The NMS changes the values of variables stored within managed devices.
3. Trap command: It is used by managed devices to asynchronously report events to the NMS. When certain types of events occur, a managed device sends a trap to the NMS.
4. Traversal operations: These operations are executed by the NMS for determining variables supported by a managed device and to sequentially gather information in variable tables, such as a routing table.

SNMP Management Information Base (MIB)

MIB is a collection of hierarchically organized information which is accessed using a network-management protocol such as SNMP. MIBs include managed objects and are identified by object identifiers.

• A managed object also known as a MIB object, an object, or a MIB consists of one or more object instances, which are essentially variables. Two types of managed objects are:

    Scalar objects which define a single object instance and Tabular objects which define multiple related object instances grouped in MIB tables.

• An object identifier also known as object ID uniquely identifies a managed object in the MIB hierarchy. The MIB hierarchy can be shown as a tree with a nameless root, the levels of which are assigned by different organizations. 

Introduction: Simple Network Management Protocol ( SNMP)

LonWorks Physical Layers 3 & 4

Layer 3: Network Layer

This layer is for Destination Addressing and specifies the destination of a message on the network. This corresponds to the area and long distance codes on the telephone network. Services provided by this layer include:

• Node address information
• Routing of messages to segment and control network bandwidth usage
• Services such as determining which nodes on the network receive various messages.
• The ability to provide routers to segment the traffic and communicate between different physical media.

Layer 4: Transport Layer

This layer is for End to End Reliability and defines the type of services needed for the node messages depending on the level of reliability required by the application. The services provided are:

• Broadcast addressing
• Unicast addressing
• Multicast addressing
• Repeated service
• Acknowledged service
• Unacknowledged service
• Duplicate packet detection
• Authentication 

Layer 1 & 2

LonWorks - SNVT elec kwh

SNVT Name: SNVT_elec_kwh
SNVT Index: 13

• The number of Data Array elements required i.e the data length for SNVT_elec_kwh when specifying a Data Array name under a Map Descriptor is1.
  
• The value range allowed for this SNVT type is 0 .. 65,535 and the values outside this range will not be processed in a read or write on SNVT_elec_kwh's value data item.
  
• The suggested data array format for SNVT_elec_kwh is Uint16 i.e. 16-bit Unsigned Integer, Float format.
  
• Invalid value will always be "Not applicable" (N/A).
  
• SNVT_elec_kwh contains only one data item named Electrical energy which is measured in Kilowatt-hours. 

LonWorks – SNVT density f

LonWorks - SNVT btu kilo

SNVT Name: SNVT_btu_kilo
SNVT Index: 5

• Number of Data Array elements required i.e the Data length for SNVT_btu_kilo when specifying a Data Array name under a Map Descriptor is 1.
• The value range allowed for this SNVT type is 0 .. 65,535 and the values outside this range will not be processed in a read or write on SNVT_btu_kilo's value data item.
• The suggested data array format for SNVT_btu_kilo is Uint16, Float format.
• Invalid value will always be "Not applicable" (N/A).
• It contains only one data item named Thermal Energy which is measured in Kilo-British Thermal Units.

LonWorks - SNVT btu f

SNVT Name: SNVT_btu_f
SNVT Index: 67

• Number of Data Array elements required i.e the Data length for SNVT_btu_f when specifying a Data Array name under a Map Descriptor is 1.
• The value range allowed for this SNVT type is 0 .. 3.40282E38 and the values outside this range will not be processed in a read or write on SNVT_btu_f's value data item.
• The suggested data array format for SNVT_btu_f is 32 Bit Float format.
• Invalid value will always be "Not applicable" (N/A).
• It contains only one data item named Thermal Energy  which is measured in British Thermal Units. 

LonWorks - SNVT angle f

SNVT Name: SNVT_angle_f

SNVT Index: 49

    The number of Data Array elements required i.e the data length for SNVT_angle_f when specifying a Data Array name under a Map Descriptor is 1.
    The Value range allowed for this SNVT type is -3.40282E38 .. 3.40282E38 and values outside this range will not be processed in a read or write on SNVT_angle_f's value data item.
    The suggested data array format for SNVT_angle_f is 32-bit Float format.
    Invalid value will always be "Not applicable" (N/A).
    Like SNVT_angle, it contains only one data item named Phase/Rotation measured in Radians only.

Lonworks SNVT count f