No Parity

Parity checking is also used in communication between modems. Here, parity checking can be selected to be even (a successful transmission will form an even number) or odd. Users may also select no parity, meaning that the modems will not transmit or check a parity bit. When no parity is selected (or defaulted), it's assumed that there are other forms of checking that will detect any errors in transmission. No parity also usually means that the parity bit can be used for data, speeding up transmission. In modem-to-modem communication, the type of parity is coordinated by the sending and receiving modems before the transmission takes place. Specifically, the Peripheral Component Interconnect bus and the I/O bus controller use the odd parity method of error checking.

Parity Limitations

Parity Checking

It is also known as Vertical Redundancy Check (VRC). It is a method of adding a parity bit to a data stream to check that data for any errors. It is an elementary method of detecting simple, single-bit errors in a memory system. It requires the use of parity memory, which provides an extra bit for every byte stored. This extra bit is used to store information to allow error detection. Parity checking on newer systems normally requires the appropriate BIOS setting to be enabled. ECC-only modules cannot be used in straight parity-checking mode.

Modbus to BACnet Protocol Converters

Checksum Files

A checksum file is a reasonably small file which contains the checksum values of other files. There are many formats of checksum files, frequently proprietary or closed. However there are also numerous open and widely supported formats. Major three formats include:

1. Simple File Verification (SFV): In the binary newsgroups and file-sharing networks SFV is a well known format. In this format, CRC32 algorithm is used and the file structure supposes ambiguity. Use of this format is generally not recommended.
2. MD5SUM: This format is mostly known in open systems world. It makes use of more secure and reliable MD5 algorithm and has more convenient structure of file. The Advanced Checksum Verifier utility support both formats, but the use of MD5SUM format is strongly recommended.
3. Alternative or BSD checksum format: This is more advanced format which allows using any checksum calculation algorithm. Unfortunately Advanced Checksum Verifier does not support currently this format. 

System Integrator

File Checksums

A checksum (also known as hash sum) is a fixed size value which is computed from an arbitrary block of digital data for the purpose of detecting accidental errors that may have been introduced during its transmission or storage. It basically allows us to check the validity of something. Usually, checksums are used in data transmission contexts to detect if the data has been transmitted successfully. The integrity of the data can be checked at any time later on, by recomputing the checksum and comparing it with the stored one. If the checksums do not match, the data was certainly altered, either intentionally or unintentionally.

RSView32 Active Display System

It is a true client/server application that adds on to and extends the reach of our RSView32 HMI software. By means of RSView32 Active Display System, we can view and control our RSView32 projects from remote locations.

RSView32 Web Server

It allows anyone with a valid RSView32 user account to access snapshot views of graphic displays, tags, and alarms through any standard web browser.

Add-on Architecture

Add-on architecture (AOA) technology expands RSView32's functionality by integrating new software components directly into RSView32. We can customize RSView32's feature set by installing only those components which we require. RSView32 includes the following AOA components that we can install separately at no extra cost:

• RSView32 Messenger: It provides powerful alarm annunciation, paging, and messaging tools.
• RSView32 TrendX: It monitors real-time data and provides historical trending from RSView32 data logs.
• RSView32 SPC: It offers integrated & real-time Statistical Process Control.
• RSView32 RecipePro: It enhances RSView32 recipe management and control.
• RSLadder: It displays ladder logic for the Allen-Bradley SLC 500 and PLC-5 families of processors. 

RSLogix 5 Benefits 1

Following are the major benefits offered by RSLogix 5:

Ladder

Via RSLogix 5 all project information can be consolidated and displayed as a Project Tree with "Point-and-Click" accessibility. Numerous rungs are edited simultaneously and program using symbols that we have not yet assigned addresses to using the Program Editor. Besides, errors get corrected at our own convenience using the Project Verifier.

Cross-Reference Information

RSLogix 5 enables us to move to any rung or instruction we require by clicking on the cross-referenced item using the Online Cross-Reference. Cross-reference information can be viewed simultaneously with our control program online or on a report.

Drag-and-Drop Editing

By means of RSLogix 5 one can:

1. Add addresses to instructions by dragging them from the Data Table Monitor, Database Files, or the Address/Symbols Picker to the desired instruction.
2. Rapidly move instructions within a project or from one project to another.
3. Move data table elements from one data file to another. 

Absorptance

Absorptance also referred to as absorption factor is the property of a body which determines the fraction of the incident radiation or sound flux absorbed or absorbable by the body. It is defined as the ratio of the luminous or radiant flux absorbed by a body to the flux falling on it. It is usually represented by the Greek letter α (alpha). It was previously known as absorptivity. In the case of a blackbody, absorptance i.e. α = 1. Standard unit of absorptance is percent (%) or a factor between 0 and 1.

Compact Fluorescent Lamps - Advantages & Disadvantages

 Advantages

Compact fluorescents offer following advantages over incandescent light bulbs:

• Lower power consumption i.e. CFL consumes 1/4 the energy, and produce 90% less heat as compared to incandescent lamps.
• Longer lifetime (last up to 10 times longer than incandescent lights)
• Produce more light

Disadvantages

• Longer starts
• More expensive than incandescent lamps owing to their higher initial cost.
• CFLs are physically larger than incandescent lamps which may make them difficult to use in some light fixtures.
• Fluorescent tubes contain a microscopic amount of mercury. It is such a small amount that disposal is not generally regulated as with full size fluorescents. Hence we should use caution to avoid crushing the tubes, and dispose of them safely. 

Types of Compact Fluorescent

Compact fluorescent lamp

Compact fluorescent lamps are smaller versions of standard fluorescent lamps. They consume between 5 to 27 watts, and have a brightness and color interpretation that is equivalent to incandescent lights. Unlike standard fluorescents, they can directly replace standard incandescent bulbs. Compact fluorescent lamps (CFLs) combine the energy efficiency of fluorescent lighting with the convenience and popularity of incandescent fixtures.

Working of CFL

Compact fluorescent lamps work to a great extent like standard fluorescent lamps. They consist of two parts:

1. A gas-filled tube
2. Magnetic or Electronic ballast

The gas in the tube glows with ultraviolet light when electricity from the ballast flows through it. This in turn excites a white phosphor coating on the inside of the tube, which emits visible light throughout the surface of the tube. Compact fluorescent lamps with magnetic ballasts flicker slightly when they start. Besides, they are heavier than electronic ballasts. Electronic ballasts are more expensive than magnetic ballasts. However, they are more efficient especially at low temperatures. Most currently available CFLs have electronic ballasts.

Compact Fluorescent Lamp Main Features

by Chipkin Automation Systems

Halogen Cycle

Halogen lamp is filled with the same inert gases as incandescent lamps mixed with small amounts of a halogen gas (generally less than 1% bromine). The halogen chemically reacts with the tungsten deposit to produce tungsten halides. When the tungsten halide reaches the filament, the intense heat of the filament causes the halide to break down, releasing tungsten back to the filament. This process is known as the tungsten-halogen cycle and it maintains a constant light output over the life of the lamp. To make this halogen cycle to work following are the basic requirements:

• The bulb surface must be very hot otherwise the halogen may not effectively vaporize or fail to adequately react with condensed tungsten.
• The bulb needs to be smaller and made of either quartz or a high-strength, heat-resistant grade of glass known as aluminosilicate.

Since the bulb is small and reasonably strong due to its thicker walls, it can be filled with gas to a higher than normal pressure. This slows down the evaporation of the tungsten from the filament, increasing the life of the lamp. The higher pressure and better fill gases can extend the life of the bulb and permit a higher filament temperature which results in better efficiency.