Extech Instruments 461893 User manual

User's Manual
Digital Photo Tachometer
Model 461893

Model 461893 Ver. 1.3 Oct. 2002
2
WARRANTY
EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects in parts and workmanship for one
year from date of shipment (a six month limited warranty applies on sensors and cables). If it should become necessary to
return the instrument for service during or beyond the warranty period, contact the Customer Service Department at (781)
890-7440 ext. 210 for authorization or visit our website at www.extech.com (click on ‘Contact Extech’ and go to ‘Service
Department’ to request an RA number). A Return Authorization (RA) number must be issued before any product is returned
to Extech. The sender is responsible for shipping charges, freight, insurance and proper packaging to prevent damage in
transit. This warranty does not apply to defects resulting from action of the user such as misuse, improper wiring, operation
outside of specification, improper maintenance or repair, or unauthorized modification. Extech specifically disclaims any
implied warranties or merchantability or fitness for a specific purpose and will not be liable for any direct, indirect, incidental
or consequential damages. Extech's total liability is limited to repair or replacement of the product. The warranty set forth
above is inclusive and no other warranty, whether written or oral, is expressed or implied.
Introduction
Congratulations on your purchase of the Extech 461893 Photo Tachometer. This device
provides non-contact measurements over a wide range (5 to 100 ,000 RPM). A reflective
mark on the object to be measured is used as a target for th e meter's integral light beam.
Careful use of this meter will provide years of reliable service.
Specifications
General Specifi cations
Meter circuitry
Custom one-chip LSI microprocessor
Time base Quartz crystal
Display 5-digit (99999 count) 0.4" (10mm) multi-function LCD
Measurement 5 to 99,999 RPM in 2 ranges
Range select Automatic
Data Recording LAST / MIN / MAX readings stored for later recall
Sampling time 1 second (over 60 rpm)
Target distance 2 to 6" (50 to 150mm) depending on ambient light
Operating Temperature 32°F to 122°F (0 °C to 50°C)
Power Supply 4 x 1.5V 'AA' batteries
Power Consumption Approximately 150 mA
Weight 8.8 oz. (250 g) including battery
Size 6.7 x 2.8 x1.5" (1 70 x 72 x 37mm)
Accessories Reflective tape (23") and carrying case
Range Specific ations
Measurement Range Resolution Accuracy
RPM 5 to 999.9 RPM
1,000 to 99,999 RPM
0.1 RPM
1 RPM
+(0.05% + 1 digit)
+
(0.05% + 1 digit)

Model 461893 Ver. 1.3 Oct. 2002
3
Meter Description
1. Photo source
2. LCD Display
3. Memory record button
4. Battery comp artment on rear
5. Measure button
Meter Operation
RPM Measurements
1. Appl y a small piece of reflective tape to the object u nder test as shown below.
2. Point the meter's photo source at the tape on the object and press the Measure but ton.
Hold the meter from 2 to 6" (50 to 150mm) from the reflective tape depending on
ambient light.
3. Check that the M onitor icon flashes on the LCD indicating that the meter is sensing a
reflection from the tape. If the mo nitor does not appear check that the light source is
hitting the reflective tape at a 90
o
angle.
4. Release the Meas ure button when the display stabilizes (2 seconds approx.). Note the
LCD RPM reading.
5. If the RPM value is < 50, apply additional pieces of reflective tape (four pieces are
shown below). Divide the LCD reading by the number of reflective tapes to compute
the actual RPM (Actual RPM = Reading / 4).
Photo Tachometer
Rotating object
Reflective tape
Light source
and reflection

Support Hotline [phone]
Tech support: Ext. 200; Email: [email protected]
Repair/Returns: Ext. 210; Email: [email protected]
Website: www.extech.com
Memory Record and Recall
The meter automatically records the Mini mum and Maximum readings. These represent
the lowest and highest readings measured from the moment the Measure button is
pressed to the moment it is released. The Last reading is also recorded; this is the last
measurement taken before the Measure button is released. These stored readings can be
displayed on the LCD using the Memory button as described below:
1. Press once and hold: The Last reading is displayed followed by "LA"
2. Press again and hold: The Maximum value is displayed followed by the word "UP"
3. Press again and hold: The Minimum value is displayed followed by "dn"
Special Measurement Considerations
1. The non-reective area of the object under test must always be greater than the
reective tape area.
2. If the shaft of the object under test is re ective, it should be covered with black tape or
paint before attaching reective tape.
Battery Replacement
The low battery indication appears as "LO" on the display. To replace the batteries:
1. Slide the rear cover o the battery compartment in the direction indicated by the arrow.
2. Replace the four 1.5V 'AA' batteries and the battery compartment cover.
3. Remove the batteries if the instrument will be stored for long periods of time.
Calibration and Repair Services
Extech oers complete repair and calibration services for all of the products we sell.
For periodic calibration, NIST certication or repair of any Extech product, call customer
service for details on services available. Extech recommends that calibration be performed
on an annual basis to insure calibration integrity.
Copyright ©2002 Extech Instruments Corporation.
All rights reserved including the right of reproduction in whole or in part in any form.
more infor for Extech 461893
Phone: [phone]
Email: [e-mail]
Web. www.airconcern.co.uk
Air Concern Ltd, Building 173 Curie Avenue Harvell Didcot, Oxfordshire