HT instruments HT309 - Manual (Page 8)

HT309
EN - 7
4.3. MEASURING OPERATIONS
4.3.1. Illuminance
measurement
1. Insert the protection cover onto the photodiode sensor.
2. Switch on the instrument using the ON/OFF key.
3. If necessary, zero the display by pressing the ZERO key (see § 4.2.7).
4. Select the measuring unit Lux or Fc on the instrument by pressing the LX/FC/CD key
(see § 4.2.2).
5. Select the type of source to be tested by pressing and holding the HOLD/L.S. key for
more than 1 second (see § 4.2.1). Standard source is type “L0”.
6. Position the sensor horizontally and perpendicularly with respect to the source to be
tested. The illuminance value is shown on the display, with automatic scale change.
7. Press the HOLD/L.S. key, if necessary (see § 4.2.1) to freeze the value shown on the
display.
8. Press the MEM/READ key to save the datum, read in real time and shown on the
display, in the memory.
9. Cover the sensor and switch off the instrument at the end of measurement.
4.3.2. Luminous intensity measurement
Luminous intensity, expressed in Candles (Cd), is calculated by the instrument according
to the following formula:
Luminous intensity (Cd) = Illuminance (Lux/Fc) x Distance from source (m
2 /ft 2 )
1. Insert the protection cover onto the photodiode sensor.
2. Switch on the instrument using the ON/OFF key.
3. If necessary, zero the display by pressing the ZERO key (see § 4.2.7).
4. Select the measuring unit on the instrument by pressing and holding the LX/FC/CD key
for more than 1 second. The symbol “CD” is shown on the display.
5. Use the arrow keys S or T to select the measuring unit of distance (m or ft) and
confirm with LX/FC/CD.
6. Set the value of the distance between the measured point and the light source (only of
standard type “L0”) using the arrow keys S or T (press and hold the arrow keys for a
quick setting) and confirm with the LX/FC/CD key.
7. Position the sensor horizontally and perpendicularly with respect to the source to be
tested. The value of luminous intensity is shown on the display, with automatic scale
change.
8. Press the HOLD/L.S. key, if necessary (see § 4.2.1) to freeze the value shown on the
display.
9. Press the MEM/READ key to save the datum, read in real time and shown on the
display, in the memory.
10. Cover the sensor and switch off the instrument at the end of measurement.