MONARCH INSTRUMENT - TACH-4A / TACH-4AR Programmable Optical Tachometer - Instruction Manual - Rev 2.0

Sep 27, 2026

Instruction manual for the MONARCH INSTRUMENT programmable optical tachometer TACH-4A / TACH-4AR, providing guidance on operation, button functions, power/lock behavior, mode switching, and menu navigation. Includes specifications covering operating modes, RPM and frequency ranges, display and indicator details, power requirements, size and weight. Explains preparation and reflective tape requirements, range and decimal-point programming for resolution, factory calibration and accuracy checks, operating distance/angle limits, and mounting recommendations to ensure measurement stability.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages8

Reading Time20 min

AccessFree to download

Overview

Button Functions and Power/Lock

Specifications

Operating Modes and Ranges

Preparation for Use

Reflective Tape Placement

Range and Accuracy

Calibration

Operating Distance and Angle

Changing the Mode

1071-4850-001 Rev 2.0 MONARCH INSTRUMENT Instruction Manual TACH-4A / TACH-4AR Programmable Optical Tachometer 15 Columbia Drive • Amherst, NH 03031• [E-Mail: Support@MonarchInstrument.com](E-Mail: Support@MonarchInstrument.com) Phone: (603) 883-3390 • Fax: (603) 886-3300 OVERVIEW TheTACH-4A has 6 control buttons. Several have more than one function. POWER (LOCK) -Used to turn the instrument on, and in some cases off. It is used to initiate the timer and counter operations and to control the RPM measurement function. RECALL (STORE) -Used to recall the maximum and minimum values in RPM and SCALE modes, temporarily hold the display in the Totalize mode, and ìsaveî (store) new setups in the MENU mode. RESET (LOCK) - Resets all stored measurements in all modes back to zero. Holding RESET and pressing POWER on start-up ìlocksonî the unit in RPM and Scale modes. RESET returns scale factor to ì00001î from a previously selected scale factor. UP ARROW (!) -Advances Menu mode selections. Incrementsthe value of the selected digit when setting scale factors. LEFT ARROW (") -Turns LCD backlight on for 60 seconds in any mode. Selects menu item options in menu mode. Selects the digit to be edited when setting a scale factor. MENU - Pressing MENU then POWER will shut the instrument off. Pressing MENU then UP ARROW will enter the menu mode and display the current Menu selection. POWER ON/OFF The unit can be powered up by pressing the POWER (LOCK) button. When turning the unit on, it can be ìlocked onî by pressing and holding the RESET (LOCK) button then pressing the POWER(LOCK) button. Locking the unit on allows it to make continuous readings without holding the POWER button. When the unit is powered up, it will operate in the last mode selected prior to turn off. The TACH-4A is shipped from the factory in the RPM mode. The unit can be shut off in any mode by pressing the MENU button then POWER button. When the Lock Chevron is not displayed and no button is pressed for 60 seconds, the unit will automatically shut off. SPECIFICATIONS OPERATING MODES Push-button selectabe Menu: RPM Scale, Total, Count, Timer, Decimal, Point (Fixed or Floating), Backlight (On-Off), Serial Number, Test SPEED RANGE (RPM) 5.0 RPM to 500,000 RPM Fixed Decimal or Auto-Ranging N.I. S.T Calibration Certificate is supplied. Range (RPM) Accuracy (RPM) Resolution 5.0000-9.9999 ± 0.0001 0.0001 10.000-99.999 ±0.001 0.001 100.00-999.99 ±0.01 0.01 1000.0-9999.9 ±0.1 0.1 10,000-99,999 ±1.0 1.0 100,000-500,000 ±0 .001% of the reading FREQUENCY RANGE: 0.08 Hz to 10,000 Hz DISPLAY: 6 digit alphanumeric 0.44 inch high backlighted LCD updated twice per second INDICATORS: On Target, Low Battery, Mode, Max, Min, Instrument ìLocked Onî, Scale and Error POWER: 4 ìAAî Alkaline batteries. Rechargeable NiCad batteries optional SIZE: 6.2î x 3. 74î x 1. 3î WEIGHT 14 oz. PREPARATION FOR USE TheTACH-4Ais a multi-function instrument which can be utilized as a wide range Tachometer, multi-funtion Totalizer/Counter, and a Timer (Stopwatch). The scale mode allows the instrument to be used as a Ratemeter and to scale in real engineering units for RPM and linear speed measurements. The Totalizer mode has an independent scaling capability. The TACH-4A has powerful internal optics while the TACH-4AR has identical internal optics and the capability to operate with a Remote Optical Sensor, Infrared Sensor, or Remote Laser Sensor. TACH-4A measures RPM directly without contacting the rotating object. A portion of the circumference of the rotating object is prepared by cleaning a small area and applying Reflective Tape (T-5) approximately 1/2" square. For small diameter shafts, a smaller reflective marker may be used on the circumference, but in no application should the reflective marker cover more than half the circumference of the shaft. Also, a measurement can be made on the end of the shaft by applying a small piece of

FAQs

How do the POWER (LOCK), RECALL (STORE), and RESET (LOCK) buttons affect operation?

POWER (LOCK) turns the instrument on and initiates timer/counter and RPM functions. RECALL (STORE) accesses maximum/minimum values, temporarily holds displays in Totalize mode, and saves setups in MENU mode. RESET (LOCK) clears stored measurements and can lock the unit in RPM and Scale modes during startup.

What operating modes are selectable in the menu?

The menu includes RPM, Scale, Total, Count, Timer, Decimal, Point (Fixed or Floating), Backlight (On-Off), Serial Number, and Test. Mode selection is performed using MENU and UP ARROW.

How is RPM measured using the TACH-4A without contacting the rotating object?

A portion of the rotating circumference must be cleaned and fitted with reflective tape (T-5) approximately 1/2 inch square. The marker must not cover more than half the shaft circumference. For small diameter shafts or end-shaft measurements, appropriate smaller marker placement rules are provided.

Sep 27, 2026

Upload by percent12345