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area X velocity

A type of 'open channel measurement' where a 'primary measuring device' is not used but instead the water velocity is measured and multiplied by the cross-sectional area of the channel (calculated from the measured 'head' and the channel's profile).

auxiliary display

The lower, smaller digits on the LCD display for Ultra units.

auxiliary input

An analogue input fitted to an controller so that a 4-20mA loop powered sensor can be used in place of an ultrasonic transducer or to allow the input from velocity sensor in .

blanking distance

The range close to the transducer where echoes cannot be detected. See also 'ringdown'.

BS3680

The British Standard for 'open channel measurement' defines certain types of flume and weir, their installation and the calculations required to get a flow rate from a measured 'head'.

communicator

Remote keypad for programming your instrument. version has a display and connects to the RS232 port via a cable. Ultra version uses infra red communication.

DATEM

Digital Adaptive Tracking of Echo Movement - Pulsar's unique and proven digital mapping software which tracks the true echo as it moves whilst dynamically eliminating false echoes. Click this for more details on DATEM.

dead zone

The range close to the transducer where echoes cannot be detected. See also 'ringdown'.

differential

Some units in our Ultra range allow connection of two transducers. This enables calculation of the difference between two levels in order to view or provide control functions from it.

distance

The distance from the face of the to the measured level.

echo confidence

A measurement of the reliability of the current reading. 100% indicates that there are no competing echoes. Lower values may indicate that the unit is choosing the 'best' of two or more echoes.

empty distance

Normally the distance between the transducer and the bottom of the vessel or channel being measured. It defines the 'zero level' or datum from which 'span' and 'set points' are measured.

fail safe

When a 'loss of echo' condition persists, the controller will indicate fail safe and take any actions that have been pre-programmed for relays and analogue outputs.

far blanking

The zone beyond the 'empty distance' where valid echoes can still be detected, normally expressed as a percentage of the 'empty level'.

fascia mount

A controller unit with a display and key pad designed for fitting onto the front of a panel. See product mounting options.

flume

Often made from Stainless Steel, concrete or GRP and installed into a straight channel so that 'open channel measurement' can be made using measurement of the 'head' only. A type of 'primary measuring device'.

H.A.L.L.

Height Above Loss Limits - an indication of the height of the tracked echo above the threshold for valid echoes.

head

In 'OCM' (also known as Open Channel Flow) applications the head is the depth of water upstream giving rise to the flow through a flume or weir. It is the difference between the 'zero flow' level and the actual level.

level

The depth of the measured material above the 'empty level' or zero level.

LOE

The state where an ultrasonic measurement cannot detect a valid echo (Loss of Echo).

loss of echo

The state where an ultrasonic measurement cannot detect a valid echo.

near blanking

The range close to the transducer where echoes cannot be detected. See also 'ringdown'.

OCM

Measurement of flow rate using the instantaneous 'head' of water in a channel over a weir or through a flume.

open channel flow

Measurement of flow rate using the instantaneous 'head' of water in a channel over a weir or through a flume.

PMD

A structure through which water flows according to a mathematical relationship between 'head' and flow. This relationship allows the volume of flow to be calculated. (See also BS3680)

primary measuring device

A structure through which water flows according to a mathematical relationship between 'head' and flow. This relationship allows the volume of flow to be calculated. (See also BS3680)

panel mount

A controller unit with a display but no keypad designed for fitting onto the front of a panel and operated with a remote programmer or via RS232. See product mounting options.

program mode

Put the instrument into 'Program mode' to program it for your application. Accessed by entering the password 1997 (default), measurement is suspended while parameter values are changed.

programmer

Remote keypad for programming your instrument. Blackbox version has a display and connects to the RS232 port via a cable. Ultra version uses infra red communication.

quick setup

A handy menu which guides the user through only the parameters that are necessary to set up their particular application. Just enter the application details as they are requested to get the unit up and running quickly.

rack mount

A controller designed to fit into a 19" sub rack with a display only and operated with a remote programmer or via RS232. See product mounting options.

ringdown

The time that the transducer takes to stop vibrating after it has emitted a sound pulse.

run mode

The normal mode of operation when the transducer is pulsing and the display indicating as programmed.

sensor

A device which detects or measures a physical property and records, indicates, or otherwise responds to it. Compare to the definition of transducer.

sound path

The route the sound takes from the transducer to the measured surface and back to the transducer.

space

The remaining space above the material up to the high level set by the 'span'.

span

Sets difference in level between empty and full and defines the 4 and 20mA values for the analogue output.

surface mount

A controller in an IP65 rated enclosure with display and keypad designed for fitting to a vertical surface.

temperature compensation

Air temperature changes will affect the speed of sound and therefore the accuracy of any ultrasonic measurement system. Pulsar transducers incorporate an internal sensor which measures the temperature at the transducer and automatically reduces any inaccuracy. Some systems will have a separate sensor if the temperature at the transducer is not representative of the whole 'sound path'. Pulsar's unique DUET transducer dynamically measures the sound velocity and thereby achieves even better accuracy over changing climate conditions.

test mode

Some units can simulate a level to allow the testing of relays and analogue outputs with connected equipment. (See P980 in your manual if available).

time of flight

the time taken for the sound to travel from the transducer to the target and back.

transducer

A device that converts variations in a physical quantity, such as pressure or brightness, into an electrical signal, or vice versa. Compare to definition of sensor.

ultrasonic

Using sound with a frequency above the normal audible range (i.e. above about 20kHz). Pulsar transducers operate in the range 20kHz to 125kHz.

ultra wizard

Pulsar controllers are capable of a huge range of functionality. To make set up easier and quicker we've added the Ultra Wizard to enable you to configure a unit quickly for three basic application types (where available): Level/Volume, Pump Control or 'OCF'. 'Quick Setup' takes you through the rest.

wall mount

A controller in an IP65 rated enclosure with display and keypad designed for fitting to a vertical surface. See product mounting options.

weir

A specifically shaped barrier or cut-out in a plate installed in a channel or tank so that 'open channel measurement' can be made by measurement of the 'head' only. A type of 'primary measuring device'.

zero flow

The level of water in a flume or over a weir at which no flow takes place i.e. level with the crest of the weir or flume (not necessarily equal to the empty distance).