Siemens Pacemaker UM344-2 Manuel d'utilisateur télécharger pdf (Page 155)

GLOSSARY UM344-2

September 1995

DAMPING - A user selectable output characteristic that increases the response time of a transmitter to

smooth the output when the input signal contains rapid variations.

DIN - Deutsche Industrial Norms - A German agency that sets engineering and dimensional standards

and has world-wide recognition.

DIN 43760 - The standard that defines the characteristics of a 100 ohm platinum RTD having an R

versus T curve with an Alpha of 0.00385 ohms per ohm per degree C.

DIGITAL SIGNALING - The high frequency HART signal.

EXPLOSION-PROOF ENCLOSURE - An enclosure that can withstand an explosion of gases within

it and prevent the explosion of gases surrounding it due to sparks, flashes, or the explosion of the container

itself, and maintain an external temperature which will not ignite the surrounding gases.

FIELD INSTRUMENT - A network element that uses current variation for digital signaling or digital

plus analog signaling.

HART - Highway Addressable Remote Transducer - A communication protocol that provides

simultaneous analog and digital signaling between master and slave devices. It is supported by the HART

Communication Foundation.

HART NETWORK - A single pair of cabled wires and the attached communicating HART elements.

LOWER RANGE LIMIT (LRL) - Determined by the transmitter's range, this is the lowest value of the

measured variable that the transmitter can be configured to measure.

LOWER RANGE VALUE (LRV) - Representing the 4 mA point in the transmitter's output, this is the

lowest value of the measured variable that the transmitter is currently configured to measure.

INTRINSICALLY SAFE INSTRUMENT - An instrument which will not produce any spark or

thermal effects under normal or abnormal conditions that will ignite a specified gas mixture.

MAXIMUM OVERRANGE - The maximum pressure (static plus differential) that can safely be

applied to a transmitter.

MULTI-DROP NETWORK - A HART Network having from one to fifteen field instruments that are

parallel connected on a single 2-wire cable. This Network uses digital signaling only. Analog signaling is

not employed.

NETWORK - A Network includes the following items:

Ÿ Transmitter(s)

Ÿ Network Element (controller, recorder, passive non-signaling element, or other device)

Ÿ Cabling interconnecting these devices

Ÿ Barriers for intrinsic safety, if installed

Ÿ Current sense resistor

NETWORK ELEMENT - Any field instrument or Primary or Secondary Master.

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Siemens Pacemaker UM344-2 Manuel d'utilisateur Page 155