Dwyer Series PUF - Manual (Page 10)

1: General Description
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Dual function numerical keypad
The block of keys shown in the center of the keypad in Figure 1.4 are dual function keys. They can be used to
enter straight-forward numerical data, select the displayed flow units or provide quick access to frequently
required control menus.
1.4.3 Power supply and battery charging
Operating power is provided by an internal battery that can be charged from the utility supply using the supplied
external charger. When you first receive the unit you must put the battery on charge for a minimum of 6.5hrs
before use. A fully charged battery will power the instrument for up to 20hrs depending on the output utilization
and backlight usage.
The backlight can be selected to be either permanently OFF, illuminated for 10 seconds, 30 seconds or 1 minute
every time a key is pressed, or permanently ON – as configured in the Setup Instrument menu. If the backlight
is active continuously it will reduce the available battery operating time to 8hrs. Similarly, if the 4 to 20 mA output
is used constantly at 20 mA, the battery life would reduce by 50%. It is therefore beneficial to turn off the backlight
and 4 to 20 mA output facilities when they are not required.
When the instrument is operating in the ‘Flow Reading’ mode, the percentage battery charge level is displayed
symbolically on the LCD screen. A warning message is triggered if the charge falls to approximately 30%, at
which point there is up to four hours of battery operation remaining, depending on usage. The battery can be
charged both while the instrument is in use or when switched off. The instrument’s internal data is stored in non-
volatile memory and will not be lost even if the battery discharges completely.
1.5 Transducers
Two sets of ultrasonic transducers are provided as standard. When setting up the instrument it will indicate the
appropriate transducer set to use for a particular application, depending on data entered by the user. Default pipe
ranges are programmed into the instrument and most of the time there will be no need to use an alternative
transducer set to the one suggested by the instrument. However, if circumstances dictate that a different set must
be used, it is possible to manually program the instrument to accept the alternative set.
Transducer set 'A'
Supplied as standard for use on pipes of 0.5 to 4.5 inches (2 to 115 mm) outside diameter.
Transducer set 'B'
Supplied as standard for use on pipes 2 to 79 inches (50 to 2000 mm) outside diameter.
Transducer set 'D'
Type 'D' transducers are optional equipment that can be used by the PUF on pipes from 59 to 197 inches (1500
to 5000 mm). They are supplied complete with ratchet straps for ‘diagonal mode’ attachment.
Key Point: The battery is not a user-changeable item. The instrument must be
returned to your distributor if the battery needs replacing.
Key Point: Only use the supplied charger, or special adaptor lead. Failure to comply
with this will invalidate your warranty.
Key Point: Each transducer set has its designed working parameters and there are
limitations as to how far these can be extended in the field without degrading the
instrument’s sensitivity and accuracy. Contact Dwyer for advice if needed.