Horizon Fitness P-1000 Service manual

HORIZON INSTRUMENTS, INC. Title: P-1000 INSTALLATION & INSTRUCTION MANUAL Number: P103050 Revision: EPage: 1 of 23
P103050 – P-1000 INSTALLATION & INSTRUCTION MANUAL

HORIZON INSTRUMENTS, INC. Title: P-1000 INSTALLATION & INSTRUCTION MANUAL Number: P103050 Revision: EPage: 2 of 23
REVISION PAGE
ORIGINAL NUMBER NEW NUMBER DATE INITIAL DESCRIPTION
P103050 Rev. A P103050 Rev. B 04/24/91 tjkII Added Graphics
P103050 Rev. B P103050 Rev. C 09/16/91 tjkII Updated for STC Release
P103050 Rev. C P103050 Rev. D 03/12/92 tjkII
Added installation checklist,
landscape format used, new cover
graphic, revised features section
and the warranty changed.
P103050 Rev. D P103050 Rev. E 05/01/03 GAZ Address change with minor text
changes.

HORIZON INSTRUMENTS, INC. Title: P-1000 INSTALLATION & INSTRUCTION MANUAL Number: P103050 Revision: EPage: 3 of 23
TABLE OF CONTENTS
Introduction 4 Maintenance 19
P-1000 Features 5 Trouble-Shooting 19
Technical Specifications 6 Common Failures of Ignition System 21
RTCA Environmental Qualification Statement 7 Warranty 22
Certification 8
Theory of Operation 9
Display Features 10 Figure 1, P-1000 Features 5
Liquid Crystal Display 10 Figure 2, Typical Signal on Magneto P-Leads 9
Status Indicators 10 Figure 3, Typical Magneto Electrical Installation 9
RPM ACR Indicators 11 Figure 4, Magneto Ignition System Electrical Diagram 10
MAG-DROP Display Mode 11 Figure 5, Rear Panel Connections 16
Operation 11 Figure 6, Typical Single Engine Magneto Locations 16
LED Dimming 11 Figure 7, Optimum LCD Viewing Angles for Installation 18
Tachometer Control 12 Figure 8, Typical Wiring Diagram 18
Engine Clock 12
Reset 12
Installation 13
Static Precautions 13
Unpacking and Inspecting the Equipment 13
The Installation/Check-Out Sequence 13
Connections 16
Removal of Mechanical Tachometer 17
Instruments Mounting 17
Circuit Breaker 18

HORIZON INSTRUMENTS, INC. Title: P-1000 INSTALLATION & INSTRUCTION MANUAL Number: P103050 Revision: EPage: 4 of 23
INTRODUCTION
Thank You for purchasing the Horizon Instruments’ P-1000 Digital Aircraft Tachometer. Many features have been incorporated into the
design of the P-1000 insuring simple operation and long life. The P-1000 represents the state-of-the-art in applying computer
technology to aircraft engine control and will prove to be invaluable in the reliable and safe operation of your aircraft.
The P-1000 functions as two fully independent digital tachometers that monitor the signals received from the primary circuits of the
aircraft’s magnetos. The internal right and left tachometers independently determine engine RPM, which is then average and displayed
for the pilot. The superior reliability of the tachometer design is due to the use of two separate magneto signals to generate two identical
RPM readings. If either magneto fails, the tachometer will continue to display RPM from the remaining functional magneto. No external
probes or sensors are required to be installed in the harsh engine environment, further reducing the possibility of failure, and simplifying
installation.
Easy installation is facilitated by wiring the P-1000 to the P-Leads of the ignition switch. In most cases, no additional wires need be run
into the engine compartment.
To be sure of obtaining the best possible performance from the P-1000 please be sure to read this Instruction Manual carefully and
become thoroughly familiar with the operation of the P-1000 before staring its use.
KEEP THIS MANUAL HANDY FOR FUTURE REFERENCE.

HORIZON INSTRUMENTS, INC. Title: P-1000 INSTALLATION & INSTRUCTION MANUAL Number: P103050 Revision: EPage: 5 of 23
ARight Magneto Signal Status Indicator. Turns on with the Loss of Signal from the Right
Magneto. Flashes when the Right Internal Tachometer is Disabled.
BMagneto Error Indicator. Illuminates to indicate that there is a difference in RPM
reported from each Magneto.
CLeft Magneto Signal Status Indicator. Turns on with the Loss of Signal from the Left
Magneto. Flashes when the Left Internal Tachometer is Disabled.
DGreen, “Normal Operating” Range Indicator. Illuminates when the Engine RPM is
within its specified normal operating ranges.
EYellow, “Warning, Cautionary or Transient” Range Indicator. Illuminates when Engine
RPM is within its specified Cautionary or Transient Operating Ranges.
FRed, “Restricted Operating” Range Indicator. Illuminates when the Engine RPM is
within its specified Restricted Operating Ranges.
UP TO FIVE SEPARATE RPM RANGES MAY BE FACTORY PROGRAMMED.
GPlacard Area
HFull 4 Digit High Visibility Back-Lit ½” Liquid Crystal Display
IRPM Overspeed Trap Recall Button/Right Tachometer Enable/Disable.
JRPM Overspeed Trap Clear Button/Indicator Dimmer.
Figure 1, P-1000 Features KEngine Hours Recall Button/Left Internal Tachometer Disable. ENGINE HOUR METER CAN
BE FACTORY PRE-SET TO START WHERE THE REPLACED TACHOMETER STOPPED.
Two fully independent tachometers in one panel-mounted instrument increase tachometer reliability in case of either magneto’s
failure. Tachometer monitors both magneto P-Leads for redundant RPM sensing and magneto performance comparisons. Non-Volatile
memory won’t forget engine hours or factory pre-sets, no battery required. Eliminates tachometer cables, oil seal problems and accuracy
problems associated with mechanical tachometers. Light weight, sturdy construction, easy to install.
Long term stability due to the use of all digital techniques, accuracy better than 1 RPM. Vibration, temperature, and
electromagnetic interference, do not affect accuracy. Detection of RPM differences between magnetos and possible magneto failure.
Automatic display of “MAG-DROP” RPM when a magneto pre-flight is performed. Visual indication of possible “HOT-MAG” or shorted
magneto conditions. Operates with any number of engine cylinders.

HORIZON INSTRUMENTS, INC. Title: P-1000 INSTALLATION & INSTRUCTION MANUAL Number: P103050 Revision: EPage: 6 of 23
TECHNICAL SPECIFICATIONS
Input Frequency Range: Up to 400 magneto firings per second, per tachometer
12,000 RPM on a 4 cylinder engine, 5,333 RPM on a 9 cylinder engine
Input Signal Voltage: 100 to 1000 Volts AC
Accuracy: +/- ½ RPM, each tachometer
Cylinder Configurations: 4,6,7,8,9,11,12,14
Input Impedance: Greater than 500,000 ohms, each tachometer input
Power Requirements: 7.5 – 31 Volts, DC, 200 ma. max
Environment:
Weight: 1.5 lbs.
Dimensions: 3 inch MSM33638 Case, 2 ¾” deep
Switch Operational Life: Greater than 250,000 cycles
Cabling: Shielded P-Lead wire to ignition switch. MS3106A-14S-6S Connector with AN-3057-6 Strain Relief
MTBF 20,000 Hours
Warranty: Limited Two Years, Parts & Labor.
Engine Hours Clock: Accurate to less than 1 hour error in 2000 hours. Records real time when engine RPM is greater than 800.
Software Certifications: Software certified to RTCA DO-178A, level 2.

HORIZON INSTRUMENTS, INC. Title: P-1000 INSTALLATION & INSTRUCTION MANUAL Number: P103050 Revision: EPage: 7 of 23
The P-1000 Electronic Digital Engine Tachometer is designed to meet the following environmental test categories of RTCA DO-160-C.
CONDITIONS PARAGRAPH
NUMBER DESCRIPTION OF CONDUCTED TESTS CONDITIONS PARAGRAPH NUMBER DESCRIPTION OF CONDUCTED TESTS
4 Tested to categories A1 & B1. Fluids Susceptibility 11 Equipment Identified as “X”.
No Test Required.
4.5.1 Ground Survival (-55 C) & Low Operating
Temperature Tests (-20 C) Sand & Dust 12 Equipment Identified as “X”. No Test required.
4.5.2 Ground Survival (+85 C) & High Short Time Operating Temperature Test (+70
C). Fungus 13 Equipment Identified as “X”.
No Test Required.
4.5.3 High Operating Temperature Test (+55
C) Salt Spray 14 Equipment Identified as “X”. No Test Required.
4.6.1 Altitude
(+25,000Ft) Magnetic Effect 15 Tested Per Category “Z”. No compass defection in each axis.
4.6.2 Decompression Tests
(8,000Ft to 25,000Ft) Power Input 16 Tested Per Category “B”.
EUT operated normally
during all test conditions.
Temperature
&
Altitude
4.6.3 Overpressure Tests
(-15,000Ft) Voltage & Spike, Conducted 17 Tested Per Category “B”.
EUT displayed no malfunctions or
degradations during testing.
Temperature Variation 5 Tested Per Category “B”. Equipment will withstand better than 5 C/min
temperature change.
Audio Frequency
Conducted Susceptibility 18 Tested Per Category “B”.
EUT displayed no malfunctions or
degradations during testing.
Humidity 6 Tested per Category “A”.
95% Humidity Induced Signal Susceptibility 19 Tested Per Category “B”.
The EUT showed no signs of susceptibility
during this test.
7.2 Operational Shock Test, 6gs in 11ms. ½
sine, 3 shocks per axis, each direction. Radio Frequency Susceptibility 20 Tested Per Category “U”.
The EUT showed o signs of susceptibility
during this test.
Shock
7.3 Crash Safety Test, impulse and Sustained Shock. 15gs in 11ms. ½ sine performed
on each axis. Radio Frequency Emissions 21 Tested Per Category “B”.
The EUT’s emissions were within the test
requirements.
Vibration 8 Tested per “Standard Vibration” requirements. Resonance scans detect no
resonance in each axis.
Lightning Induced Transient
Susceptibility 22 Tested Per Category “K”.
These tests had no
effect upon the EUT.
Explosion 9 Test Not Applicable. Lightning Direct Effects 23 Tested Per Category “X”.
Waterproofness 10 Equipment Identified as “X”.
No Test Required. Icing 24 Tested Per Category “X”.

HORIZON INSTRUMENTS, INC. Title: P-1000 INSTALLATION & INSTRUCTION MANUAL Number: P103050 Revision: EPage: 8 of 23
CERTIFICATION
The P-1000 is installable into an aircraft under one of the following conditions:
1. With an STC issued for your model aircraft allowing the P-1000 to replace the existing mechanical tachometer.
2. With a one-time-only STC issued for installation of the P-1000 on your aircraft, this is typically referred to as a “Field Approval”.
A P-1000 purchased with an STC for replacement of the existing mechanical tachometer will have attached to this documentation
package:
Supplemental Instructions and Drawings pertaining to the specific installation of the P-1000 in the indicated aircraft.
Flight Manual Supplement
A copy of the applicable STC
The Supplemental STC information supplied with a P-1000 is dependent upon the information supplied to Horizon Instruments, Inc. at the
time the P-1000 is ordered. If this information is erroneous, applicable to a different type of aircraft, or missing, do not proceed with
installation. Contact the Horizon Instruments, Inc. Technical support staff for further instructions.
NOTE:
The STC Approval accompanying a P-1000 tachometer is considered proprietary information by horizon Instruments, Inc. and is not
applicable to any other manufacturer’s equipments.

HORIZON INSTRUMENTS, INC. Title: P-1000 INSTALLATION & INSTRUCTION MANUAL Number: P103050 Revision: EPage: 9 of 23
THEORY OF OPERATION
The P-1000 operates by timing the alternating electrical signals
generated by an operating magneto, see Figure 2, and mage
available on the magneto’s “P” or grounding leads. Because
reciprocating engine aircraft have two magnetos on each engine
(See Figure 3), the P-1000
provides two terminals for
connection to these “P” leads of
the right and left magnetos of the
engine. These “P” lead signals
are generally only a few hundred
volts as compared to the
secondary output of the magneto,
which may generate tens of
thousands of volts used to create sparks at the spark plugs.
RPM is derived from the repetition rate of the signals received from
the magnetos, and not the amplitude or shape of these signals. This
rate corresponds to the firing of the engine’s spark plugs, and thus,
the turning of the engine.
The Microprocessor functions as two internal tachometers. It has the
ability to compare and store the RPM of each tachometer.
A difference of RPM reported from the two magnetos of the same
engine indicates that one of the magnetos may be failing (i.e. Mis-firing, severe fouling, sticking or floating points, etc.).
The RPM displayed on the LCD is the average of the right and left tachometer’s RPM. Thus, if either tachometer begins to fluctuate or act
erratically, due to failure in its ignition system, the error will show in the display. Mechanisms are provided to mask these erroneous RPM
values and allow operation from the signal of the functional magneto.
Loss of a signal from either magneto is detected by the corresponding internal tachometer and a signal status indicator is turned on to
indicate the error. Short term (<½ second) differences between the right and left tachometers are also indicated to the pilot with a yellow
status indicator.

HORIZON INSTRUMENTS, INC. Title: P-1000 INSTALLATION & INSTRUCTION MANUAL Number: P103050 Revision: EPage: 10 of 23
Engine hours are recorded in real time beginning when the
engine is assumed to be able to sustain combustion, at or
above 800 RPM. A high accuracy engine clock yields true
TBO times (engines are rated in real hours, not RPM-hours)
and more accurate fuel consumption calculations.
Using the internal microprocessor to compare RPMs from
each internal tachometer against a previously known
highest RPM, and storing the new highest RPM creates the
“Overspeed Trap” feature. Provisions are made to clear
this trap at any time. The Overspeed Trap is saved when
the P-1000 is turned off.
DISPLAY FEATURES
LIQUID CRYSTAL DISPLAY
The P-1000 provides easy to read ½ inch high characters
on a liquid crystal display (LCD). A “straight line”
(displayed using hyphens) is displayed on the LCD when the
P-1000 is not receiving a signal from either magneto. This
is generally noticeable when the P-1000 is turned on and
the engine is not started.
STATUS INDICATORS
When no signal is received from either the right magneto or left magneto (See Figure 1), the P-1000 will turn on a corresponding right or
left red magneto signal “Status” indictor. The status indicators are located on the upper left of the tachometer face and can indicate a hot
magneto (open circuit) or grounded magneto (breached insulation or broken ignition switch) condition. The indicators turn on after ½
second passes without receiving a pulse from a magneto, and will turn off when the signal is restored.
Another status indicator is located between the red magneto signal indicators. This yellow indicator is a warning that the P-1000 has
detected different RPM from the signals provided by each magneto. This is typical of a failing set of points or an intermittent wiring
problem. The yellow status indicator may be accompanied by a red magneto signal status indicator, but under some conditions, may
appear by itself. See the Troubleshooting section for more information. This indicator operates as a threshold set at the maximum
allowable difference between the mag-drop readings of each magneto.