For longer duration measurements, the trigger latch on the side of the pistol
grip handle can be depressed after pulling the trigger, and the instrument
may be mounted on the 1/4-20 threaded bushing at the base of the handle.
When the trigger is released, the Tachometer will hold the last measurement
taken and display it for up 90 seconds.
On very small shafts, the Phasar-Tach will work down to a reflective tape
size of approximately 1/8 inch [3.2 mm] square. However, with this small
tape size, it would be necessary to operate the instrument very close to the
rotating shaft and insure it is held steady. For normal operation, a tape size
of approximately 1/2 inch [12.7 mm] square or larger is recommended, and
on very large diameter shafts or for very high-speed applications, a larger
size piece of tape may be required. It is also recommended that the reflective
tape be viewed just slightly off the perpendicular. The Tachometer will
operate at angles from 0 to 45 degrees, but best results are obtained by
aiming the instrument at the reflective tape at approximately a 10 to 20
degree angle. This insures that only pulses from the reflective tape are
received by the tachometer and minimizes the problem of interference from
a highly polished surface or varying ambient lighting.
USING THE PHASAR-TACH WITH AN REMOTE OPTICAL
SENSOR (ROS-5P)
The -R version of the tachometer has a provision for using the optional
ROS-5P Remote Optical Sensor. In addition to the standard built-in optics,
a 1/8 inch [3.5 mm] phone plug is provided on the front panel to accept an
ROS-5P Remote Optical Sensor. A toggle switch on the optics panel selects
internal or remote operation.
For applications requiring the ROS-5P Remote Optical Sensor, move the
Remote/Internal switch to the remote position to disable the internal optics
of the Tachometer. When the trigger is pulled or latched, the ROS-5P
3
Remote Optical Sensor can be used for measurements. The ROS-5P operates
3 feet [0.9 m] and ±45° from the reflective tape.
NOTE:
The standard ROS-5P cable length is 8 feet [2.4 m]. Longer cables
up to 100 feet [30.5 m] are available.
CALIBRATION AND SELF-TEST
The Tachometer is a crystal controlled digital instrument that requires no
calibration. However, the accuracy of the instrument can be checked at any
time by aiming it at an old style fluorescent light and observing 7200 ±2
RPM. In countries with 50 Hz. power line frequency, the display will read
6000 ±2 RPM.
NOTE:
The Tachometer will not read on energy-efficient fluorescent lights.
4
Remote/Internal
Switch
Internal Optics
Lens
Recharger Jack
Figure 1 Phasar-Tach LCD-R
with Optional Remote Sensor (ROS-5P)
