Using the 1U6602 Photo-Tach Group{0775} Caterpillar

Introduction

The 1U6602 Photo-Tach (Tachometer) Group provides a safe, accurate, digital, noncontact method for measurement of rotational speed. It measures rpm by directing an integral light source onto a piece of reflective tape. The photo-tach can be used to measure the rotational speed of any part, where a piece of reflective tape can be positioned. During use the photo-tach will count the reflected light pulses.

To use the 1U7771 Photo-Tach, aim it at the reflective tape (target), squeeze and hold the trigger on the pistol grip and read the speed. The last reading is displayed for about one minute after release of the trigger. If the trigger is squeezed again, new measurements begin immediately.

The rpm is directly displayed on a liquid crystal digital (LCD) four and one-half digit display in numbers 10.2 mm (0.4") high. The 1U7771 Photo-Tach provides the noncontact measurement of rotational speed for a range of 50 to 20,000 rpm, with an accuracy of ± 1 rpm.

Components of 1U6602 Photo-Tach Group

(1) 6V3073 Case. (2) 1U7772 Foam Block. (3) 1U7771 Photo-Tach. (4) Batteries. (5) 1U6605 Reflective Tape.
Optional Items:
(6) 1U6603 110/220 VAC Recharger. (7) 1U7445 Nickel Cadmium Batteries (not shown) - 4 required.

Specifications for 1U6602 Photo-Tach Group

MEASUREMENT RANGE: 50 rpm to 20,000 rpm.

ACCURACY: ± 1 rpm.

RESOLUTION: 1 rpm.

DISPLAY: 4 1/2 digit, 10.2 mm (0.4") high liquid crystal.

ON TARGET INDICATION: Steady illumination of the plus sign.

OPERATING ENVELOPE: Range: 0 to 0.92 m (0 to 3') from reflective tape. Angle: Up to 45 degrees from perpendicular to reflective target.

LAST MEASUREMENT MEMORY: Displays last measurement approximately one minute after trigger release.

POWER ON SWITCH: Pistol grip trigger may be locked on with latching push button for longer duration measurements.

OPTICAL SYSTEM: Single lens reflex. Visible light source.

TIME BASE: Crystal controlled.

POWER SOURCE: Four "AA" batteries. Recharger socket provided for optional rechargeable batteries.

SIZE: 83 mm x 45 mm x 156 mm (3.25" x 1.75" x 6.13").

WEIGHT: Approximately 0.57 kg (1.25 lbs).

Operation

The 1U7771 Photo-Tach measures rotational speed from a single pulse per revolution. This pulse is supplied by attaching a piece of 1U6605 Reflective Tape to the rotating part, in an easily accessible location. The 1U7771 Photo-Tach is equipped with a built-in steady state DC light source. This light source provides a light beam that is aimed at the reflective tape target on the rotating part. A target about 12.7 mm (0.5") square, or larger, is recommended for normal operation.

The light pulse that is reflected from the rotating part is received back through a single lens reflex optical system, and read by a photo cell inside the photo-tach. The plus (+) sign on the left side of the display, provides an "on target" indicator to verify that the photo-tach is on target, and is receiving valid information. The photo-tach then computes the rotational speed, and displays it to a resolution of 1 rpm.

To use the photo-tach, aim it at the reflective tape while holding it at a distance of 25.4 mm (1.00") to 0.92 m (3') from the rotating part. Squeeze the pistol grip trigger, and read the indicated speed. The display is updated once per second.

For longer duration measurements, the trigger may be latched in the "ON" position, with a push button located on the side of the pistol grip handle. The entire instrument may be mounted on a tripod, or other suitable mounting fixture, with a 1/4-20 threaded bushing in the base of the handle.

On very small shafts, the photo-tach will work with a reflective tape target size that is as small as 3.2 mm (.125") square. With a target this small, however, it will be necessary to have the instrument close to the rotating shaft. Make sure the photo-tach is held steady.

On large diameter shafts, or high speed applications, a target larger than 12.7 mm (0.5") may be required. It is also recommended that the target be viewed just slightly off the perpendicular.

The photo-tach will operate at angles from 0 to 45 degrees, but best results are obtained by aiming the instrument at the target from an angle of 5 to 20 degrees. This insures that only those pulses from the reflective tape are received by the instrument. This minimizes the problem of interference from a highly polished surface, or varying ambient lighting.

The photo-tach can be used to measure the rotational speed of any part, where a piece of reflective tape can be positioned.

Batteries

The photo-tach requires four "AA" size batteries that are located under the hinged cover. To check or remove the batteries, grip the tapered cover at the optical lens end of the instrument and pull UP. The cover is hinged at the display end of the instrument, and pivots fully out of the way to permit access to the batteries.

The photo-tach will operate for up to 8 hours continuous on a single set of batteries, depending upon the type of batteries used. If desired, the photo-tach may be powered by the optional 1U7445 Nickel Cadmium Batteries. These batteries are rechargeable, and can be charged with the built-in charging system and the 1U6603 Recharger. To charge the 1U7445 Batteries, a connector jack next to the photo-tach optical lens is available to connect the 1U6603 Recharger. A complete recharge takes 14 to 16 hours.

Warranty/Repair Information

The 1U7771 Photo-Tach is warranted to be free from defects in material and workmanship for a period of 12 months from the original date of purchase from Caterpillar Inc. If the 1U7771 Photo-Tach does not operate correctly, lift the lid of the instrument and check to make sure the batteries are properly installed, and that they are in good condition.

If the instrument still does not operate correctly, use one of the addresses or telephone numbers that follow, to contact the Caterpillar Service Technology Group.

Telephone:

1-800-541-8665 (Inside Illinois)

1-800-542-8665 (Outside Illinois)

1-800-523-8665 (Canada)

Outside of North America use Telex #404435

If the tool, or any part of it, is to be sent to Caterpillar for repair, be sure to first contact Caterpillar Service Technology Group as indicated. Before sending the tool, be sure to enclose a letter that describes the problem, and give the date of purchase from Caterpillar. Tools that are less than one year old will be repaired under warranty (except for abuse). The cost for out of warranty repair will be charged to the owner.

Mailing addresses are as follows:

U.S. Mail:

UPS and EMERY only: