A Historical Perspective of "force"
Evidence of the many benefits of videographic, or paperless, recorders are the large number of suppliers that now offer these types of instruments. Some are relative newcomers to the recorder field, utilizing their expertise in electronic technology to meet user needs. One example is the recent offering of a circular chart videographic recorder with a 10-inch screen display-equivalent in size to the common paper chart versions.
Display technology has been getting better and better in sharpness of detail, with a wide range of bright colors, similar to the proven quality of a newer PC. Some models offer the flexibility of plotting records horizontally or vertically. A common screen size on such recorders is small-on the order of 76 mm wide by 38 mm high (3 in. x 1.5 in.).
Some suppliers offer a 5-inch wide display area or larger. Most are designed for panel mounting and come in a size as small as 1/4 DIN. In addition to displaying trend records or bar graphs, the instruments can be configured at will to provide large digital displays of the measurements in engineering units or small digital readings along with the trend curves.
These recorders have some form of storage media-either a 3-1/2 inch floppy disk or a PCMCIA card-which continuously stores all the measurement inputs as well as the recorder configuration. From such stored data, an operator can use a touchscreen or membrane keypad to provide such display functions as: a split screen (two trend windows), zooming, faceplate displays, alarm summaries, and selected trends (such as six out of up to 24 inputs).
The recorder's disk or card can be removed and used to download all its accumulated data to a PC that has the necessary software. An engineer can bring up any of the stored data for review and analysis, zooming in on a desired time, say, of a process upset (as well as just before and just after the event).
Videographic recorders may include a serial port that permits data to be sent, for example, over an RS-422/485 communication network directly to a PC or DCS with suitable software. This can be two-way communication. Thus, an operator at a PC in a control room could monitor the recorder readings in real-time, call for specific data, and even reconfigure the recorder.