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© TIMEWISE 32 Old Barn Road Hawthorn Woods, Illinois 60047
Part Number 1001–798A Rev 7.001
TIMEWISE
798A
RALLY
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TIMEWISE
798A
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Table of Contents
Summary of Contents for TIMEWISE 798A
- Page 1 Shift – CAST to load ÷ Odo Input Input Ratio Remote Brightness Error Format Speed Format ERROR AUXILIARY USER’S MANUAL © TIMEWISE 32 Old Barn Road Hawthorn Woods, Illinois 60047 (847) 550-5052 Part Number 1001–798A Rev 7.001 All Rights Reserved...
- Page 3 Changed the automatic LED display brightness level setting that occurs upon wake-up from idle mode. The main unit LEDs now re-illuminate at their mid-point if they were set to less than half the maximum brightness when the 798A entered the idle mode.
- Page 4 Changed the odometer pulse interrupt routine to allow an increase in the permissible odometer pulse rate. Continuous odometer pulse rates in excess of 5000 pulses/second are now tolerated, even without use of the 798A's built-in input signal divider. The visual warning indicating an overly rapid odometer pulse rate now occurs at rates in excess of 5000 pulses/second.
- Page 5 FIRMWARE VERSION HISTORY Secondly, if the Intelli-CAST mode had been active upon a CAST change, the 798A saved the previous CAST (required if the Last CAST feature is applied) at a value 0.08 mph higher than the actual previous speed. As a result, Last CAST odometer reading adjustments resulted in a slightly inaccurate correction to the calculated time.
- Page 6 Increased switch scan speed. Version 7.000 (July 30, 2019) Increased switch scan speed when using a trace modified main printed circuit board. Version 7.001 (November 25, 2019) Increased error computation speed. Option 7 and alternative LED drivers no longer mutually exclusive. TIMEWISE 798A...
- Page 7 Using the perfect time computing features of the 798A prior to running a rally, timing errors associated with typical course maneuvers (non-instantaneous starts and stops, speed changes at signs, slowing for turns, etc.) can be measured.
- Page 8 The technique is simple: Prior to the start of the maneuver, actuate and hold the switch. At the start of the maneuver, release the switch. When the maneuver RESET RESET is complete, split the 798A. Then record the timing error, elapsed time, computed time, and distance traveled during the maneuver. TIMEWISE 798A...
- Page 9 That is, whenever a “+ / – 10.00”, “+ / – 1.00”, or “+ / – 0.1” toggle switch is activated (while adjusting a speed), the 798A automatically truncates the speed to xx.x0 resolution.
- Page 10 SUPPLEMENTAL INFORMATION OPTION 6 As a safety measure, the 798A does not repeatedly increment (or decrement) the hundredths digit of the speed displays when the .01 switch is held in place for more than a half second. You must activate the switch multiple times to change the hundredths digit multiple counts.
- Page 11 0.45 seconds (or 0.45 hundredths) to the driver’s error value. See page 60 in the Instruction Manual for details. Option 9 firmware in your Timewise 798A allows you to apply a offset bias of an amount you choose to the driver’s display.
- Page 12 This may not be the fault of Appropriate the timing crew. Rather, it can be the result of imperfect correlation between the 798A clock Offset Bias and the checkpoint clock. Limited display resolution and basic uncertainties affect all timing systems.
- Page 13 :06.0 to :05.9 – but you cannot see the “.9”. That is, the error really changed by 0.1 count even though it appeared to change by a whole count. If you split the 798A at that moment, you might be splitting 0.9 earlier than you expected.
- Page 14 SUPPLEMENTAL INFORMATION OPTION 9 And if you do this test with an offset of – 0.9, splitting the 798A just as the driver’s error decrements (to the next positive whole number) will actually freeze the time of day clock 1.8 units early.
- Page 15 CAST at a preset distance Option 11 firmware in your Timewise 798A allows you to preset a distance at which a CAST is automatically executed. The rally speed that is used upon execution of the CAST is also preset.
- Page 16 The AutoCAST function does not preclude the use of the original Preset function. The same distance and speed values you set for the AutoCAST, as well as the preset calculated time, Preset Load can be loaded into the 798A via the Preset function’s “ SHIFT –...
- Page 17 52 in the instruction manual for a detailed description of the function.) Preset Logged Lastly, note that when reviewing data in the 798A’s optional datalog, an AutoCAST execution is identified by the word “ Auto ” in the AUXILIARY display.
- Page 18 SUPPLEMENTAL INFORMATION OPTION 11 This Page Intentionally Left Blank TIMEWISE 798A...
- Page 19 Limitation on Warranty and Liability Timewise warrants this equipment to be free from defects in material and workmanship for a period of two years from the date of shipment to the original purchaser. This warranty is limited to the repair and replacement of parts and the necessary labor and services required to repair the equipment.
- Page 20 How to Use For a brief description of what the 798A does, read the I N T R O D U CT I O N . Study the INSTALLATION section of the manual for suggestions of various 798A mounting This Manual methods.
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Page 21: Table Of Contents
Warranty & Repair CONTENTS About This Manual Table of Contents 798A Features Introduction SECTION 1 – INSTALLATION Mounting the 798A 10 Electrical Connection 12 Odometer Transducers 14 Transducer Selection 15 Transducer Installation 20 Final Installation Procedures SECTION 2 – OPERATION 21 Start-Up Procedure…... -
Page 22: Table Of Contents
Odo & Time Adjustments The Odo & Time Calculation Speed Changing the Calculation Speed Details…one more time 51 Transit Zones 52 Preset data Entering Preset Data Loading Preset Data 53 The Datalog Reviewing the Datalog Datalog Presentation Modes Printing the Datalog TIMEWISE 798A... - Page 23 79 Appendix B - Preventing Problems 85 Appendix C - Odometer Input Specifications 89 Appendix D - Oscillator Adjustment 90 Appendix E - Cleaning the 798A 91 Appendix F - Materials List 92 Appendix G - Technical Specifications 93 Appendix H - Minutes/Mile Table...
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Page 24: 798A Features
(–:00.1 or 99:99.9), selection at any time Selectable CAST range of 0.1 - 99.9, or 1 - 399 (mph or kph) Clock auto-synchronization compatibility to Timewise clocks Clock adjustments and synchronization to a time standard at any time Intelli-CAST™... -
Page 25: Introduction
(second). You can switch between counting in hundredths or seconds at any time; and, you can synchronize the beat of the clock to a time standard at any time. If a Timewise multi-split checkpoint clock is accessible, the 798A can be automatically synchronized to the checkpoint clock via a simple cable connection. - Page 26 A confirmation of the change is available in a resettable “amount of change” display. Subsequent to a CAST change, you may recall values that were present in the 798A at the moment of that CAST. Further, you can adjust the CAST execution mileage to a new value and the 798A will automatically correct the calculated time, appropriately using the old and new CAST speeds in the re-computation.
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Page 27: Section 1 - Installation
You will also need to spend additional time learning how to use the instrument. Do not attempt to run a rally on the same day you install the 798A. In fact, it is highly recommended that you use the instrument under simulated rally conditions before running an actual rally. -
Page 28: Electrical Connection
Ground the discharges to the front panel of the 798A are dissipated along a path that doesn’t interfere with the power supplied to the instrument. If you do not properly ground the 798A, it may 798A! fail in the presence of radio transmissions and other electrical noise. - Page 29 Also, the shorter the wire, the better. A foot is long, here. Three feet is too long! The power connections of the 798A must also be made with the utmost of care. The black wire must be connected to the negative (–) potential of the battery. The red wire must be connected to the positive (+) potential of the battery.
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Page 30: Odometer Transducers
These rings, termed “ferrite beads”, help to prevent radio frequency interference (RFI) from entering the 798A. Overly strong RFI can interfere with the operation of the 798A. For the ferrite beads to be most effective in attenuating RFI, they must be located next to the 798A. See Appendix B for more information. - Page 31 Section 1 INSTALLATION Note that there are two odometer inputs on the rear of the 798A. To use both inputs, you need two odometer transducers. The transducers may be of different types. One may be from the electronic speedometer of the vehicle, the other from a transducer you have installed.
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Page 32: Transducer Selection
The 798A can generally accommodate these slowly changing transducer signals. However, if the signal varies excessively between “on” and “off” states before settling, the 798A can mistakenly count more than one pulse. (This problem will not occur if the transducer is designed with a “photo-darlington” output transistor.) Note: Using two photoelectric transducers may cause an internal fuse to disconnect power to the odometer input connectors. -
Page 33: Transducer Installation
Transducers with the manufacturer to determine if you are restricted to passenger compartment mounting locations. Timewise closed magnetic transducers use a gasketed housing that weatherproofs the transducer, allowing it to be mounted outside the vehicle. Installation of a closed transducer is rather straight forward. Locate and disconnect the speedometer cable at one end, attach one end of the transducer to where the cable was removed, and re-connect the cable to other end of the transducer. - Page 34 Transducers past the sensing end of the transducer. The standard Timewise two-piece magnetic transducer (a.k.a. the Permalloy “sensitive” Model 217-15) is activated by either the North or South pole of a magnet. The transducer is 2" long and 0.375" in diameter. The body of the transducer is threaded along its entire length, allowing you to adjust its axial position after installation.
- Page 35 A stabilizer bar will change shape and position when the suspension moves. As mentioned, when installing the transducer, you will need to position it so the magnets will pass approximately 3/8" to 5/8" from the transducer’s sensing end. TIMEWISE 798A...
- Page 36 The transducer is considerably more durable than the plug. A bracket for the transducer must be attached to the vehicle. Timewise can supply a bracket with several pre-drilled 1/4" holes for mounting bolts and a 3/8" hole for the transducer. You can also fashion your own bracket from a steel mending plate.
- Page 37 The magnetic field of the remaining material may not be sufficient to stimulate the transducer. If you need magnets of a different shape, size, or magnetic orientation, contact Timewise. When installing the Timewise Model 217-15 transducer, you need not be concerned which pole of the magnet faces the transducer.
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Page 38: Final Installation Procedures
FINAL After installing the 798A and the transducer(s), plug the transducer(s) into the odometer input jack(s) on the rear of the 798A. If you have only one odometer transducer, install the INSTALLATION supplied jumper plug into the unused input. This allows that input to use the signal supplied PROCEDURES to the other transducer input. -
Page 39: Section 2 - Operation
The driver’s module, on the other hand, always re-illuminates at the LED brightness level being used prior to entering the power savings mode. If you do not want the displays to automatically go off while the 798A is idle, turn the rotary switch to the Next Speed position. -
Page 40: Adjusting Parameters
ADJUSTING Throughout this manual you will be directed to alter the values of rally parameters in the 798A. To do so, you must understand how to use the “+ / –” toggle switches as well as the PARAMETERS rotary switch and the RESET–SHIFT... -
Page 41: The Reset-Shift Switch
, and AUXILIARY displays is frozen. PARAMETERS While you are in the split mode, the 798A continues to keep track of time and the passage of distance internally. When you de-select SPLIT , the displays automatically update to current course values. It will be as if you had never entered the split mode at all. -
Page 42: Adjusting A Split Parameter
“hundredths” anyway, to increase your timing resolution. A unique feature of the 798A is that the counting mode of the clock may be changed at any time without introducing any timing inaccuracy. To change the mode of the clock, turn the rotary switch to its 5 o’clock, or special function, position. -
Page 43: Setting The Clock
Setting Setting the clock in the 798A consists of a sequence of steps that safeguard against accidentally changing the time. Once learned, the steps will become second nature. -
Page 44: Synchronizing The Clock
The synchronization will not change. Automatically As a convenience, the clock in the 798A can be automatically set and synchronized to the exact time of day within a Timewise Model 610, 650, or 660 Multi-Split Chronometer. -
Page 45: The Odometer
The only difference is that when a 610, 650, or 660 is sensed by the 798A, the time of day is automatically downloaded from the chronometer. To recap, follow this procedure to synchronize the 798A to a Model 610, 650, or 660 chronometer: 1. -
Page 46: Preventing Accidental Selection Of Park Or Reverse
, the alarm will again sound every ten seconds even if you had previously disabled it. † You can adjust the length of time each beep sounds when the 798A is in park or reverse. To do so, select ALARM on the rotary switch... -
Page 47: Displaying Thousandths Of Miles
Section 2 OPERATION Displaying A standard feature of the Timewise 798A is that it allows you to display and adjust the odometer in thousandths (.001) of miles. Thousandths of Miles To display “thousandths of miles” resolution in the odometers, turn the rotary switch to the special function (5 o’clock) position, and actuate the “... -
Page 48: Details, Details, Details
(xxx.xx000000). † If desired, you can enable a short delay before a truncate action is recognized. To implement the delay, turn on the 798A while holding down the... -
Page 49: Resetting The Main Odometer
As an option, Timewise can reprogram your 798A so that subsequent to a truncate being executed, the main odometer will immediately count distance (and count calculated time) even while switch continues to be depressed. -
Page 50: Selecting The Active Odometer Transducer Input
Factor on the rotary switch, actuate (and hold) the RESET switch up, and then actuate any “+ / –” switch. The 798A will begin using the other odometer input. As before, the CALCULATED TIME display shows the active input. (The... -
Page 51: Determining Your Base Factor
I n P u t 2 ” means input 2 is active. The 798A saves all factors in non-volatile memory. The factor values you enter will remain unchanged until you subsequently change them, even if the 798A had been turned off. -
Page 52: Using The Built-In Odometer Pulse Divider
† Actually, the 798A has been experimentally operated at an odometer signal rate of 10,000 pulses per second without missing a single pulse. The “divide-by” circuitry extends this rate to 1,280,000 pulses per second. No land based vehicle electronic speedometer system comes anywhere close to this limit. -
Page 53: Determining A New Factor At A Rally
If you had valid base values for the other factors in the 798A, you can use the same odometer check measurement value to calculate new values for the other factors. However, if those factors do not have valid base values, you would have to retrace the odometer check once for each of those other factors. -
Page 54: Automatic Warning Of An Odometer Transducer Failure
798A is measuring your speed, the speedometer value will momentarily decrease by 5% to 10%. (The 798A measures your speed approximately twice per second. If a pulse is skipped between speed measurements, the missing pulse will not be evident.) - Page 55 Lastly, correct base values for the unused factors (the second factor for the active input, as well as both factors for the inactive input) must have been set into the 798A. This is because the 798A computes a correction percentage for the active factor, and then applies that same percentage adjustment to each of the other factors (unless, as mentioned above, the inactive input is not receiving a signal, in which case the factors for that input are not changed).
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Page 56: Sample Factor Calculation
After a sample factor calculation is executed, the normal Compute Factor function can be executed only before the 798A counts another transducer pulse. As soon as a pulse is used to count forward motion (i.e., when the 798A is in FORWARD... -
Page 57: Fine Tuning The Odometer Factor
Fine Tuning Whenever the rallymaster gives an official mileage at a reference, you can use that information to confirm the measuring accuracy of the 798A. When doing so, you will often the Odometer notice slight deviations from official mileages. Such inconsistencies occur when the Factor rallymaster’s driving style differs from yours. -
Page 58: The Calculated Time
By using the thousandths of miles capabilities of the 798A, you can see how close you match every mileage reference given by the rallymaster. You can precisely align your odometer to the rallymaster’s official measurements at each such reference. -
Page 59: Pauses And Gains
798A counts from the exact value used by the rallymaster. If not cleared, non-zero values in those two digits would cause the calculated time to increment too soon. The result would be a slightly incorrect calculated time throughout the entire leg. -
Page 60: The Active Cast
SPEED display shows the CAST currently in use by the 798A as it computes the calculated time. The CAST shown is the average speed the 798A expects you to maintain, CAST not the speed at which you are actually traveling. - Page 61 Unique to Timewise rally computers, this important feature deserves further explanation: As you drive, the 798A not only keeps track of distance in the main and auxiliary odometers, it also has another internal odometer that records the distance driven within the “active speed section”.
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Page 62: Details, Details
For example: After traveling exactly 1.000 mile at a CAST of 30 mph, the 798A will increase the calculated time exactly 2.00 minutes. When you travel 1.005 miles, the calculated time will increase to 2.01 minutes. -
Page 63: Using Slow Speeds
If you are concerned about timing discrepancies resulting from the high measuring resolution of the 798A, it is suggested that you change CAST at locations that are exact hundredth of a mile increments. That is, instead of executing a CAST exactly at a reference, you may wish to execute the CAST just before or immediately after the reference. -
Page 64: Intelligent Casts
OPERATION Section 2 Intelligent The 798A can be set up so that the distance (and, therefore, the calculated time) for each CAST section will exactly match the rallymaster’s 0.01 mile resolution regardless of where CASTs [within the intended hundredth of a mile] you change CAST. -
Page 65: Changing The Distance Measurement And Calculated Time At The Last Cast (Post-Alignment™)
0.01 mile error using the “+ / –” toggle switches. As you change the last CAST execution point to 26.75, the 798A will add 0.02 minute to the previous section’s calculated time. This is due to the additional .01 mile traveled at 30 mph. - Page 66 L A S T CA S T switch after entering a last CAST odometer correction, the 798A temporarily disables use of the “+ / – ” toggle switches for about one second. This forestalls a change to any other parameter should you accidentally release the L A S T CA S T Post-Alignment™...
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Page 67: Automatic Calculated Time Adjustments
0.00 (or 0.000 if viewing thousandths of miles). O d o & T i m e function will work even when the 798A is split. As when adjusting any split parameter, corrections to the split calculated time will be apparent as you enter the distance adjustment, and will be included in the “live”... -
Page 68: The Odo & Time Calculation Speed
Odo & Time position. (If you change the calculation speed after entering the distance adjustment, the 798A appropriately re-computes the correction to the calculated time.) Distance adjustments you make, as well as the associated correction to the calculate time, are permanently recorded when you de-select O d o &... -
Page 69: Details
NEXT SPEED display. At the end of the transit zone, actuate CAST The 798A treats transit zones just like any other speed section. As a result, you can use the Retro-CAST™ function. If you execute a Transit in error, use the... -
Page 70: Preset Data
(e.g., 0.00 miles), a calculated time (your out-time), and a CAST. Using this information you can precisely align the 798A to the rallymaster’s values. To do so, drive to the identified landmark and enter the three official values into the appropriate displays. -
Page 71: The Datalog
† You can modify the 798A so that it stores the speed you changed “from”, rather than the speed you changed “to”, whenever a data set is saved. To do so (with version 2.001 firmware, or newer), turn on the 798A while concurrently activating the... -
Page 72: Datalog Presentation Modes
The same is true if you adjust a parameter while split and review the original split data later. Datalog You have a choice as to the way the 798A proffers data following each logging action. The data may be presented in two ways: one way allows you to quickly locate recently logged Presentation information;... -
Page 73: Printing The Datalog
For example, if the rallymaster instructs you to change speed at a specific distance, preset the odometer alarm to that value and let the 798A notify you when you reach the location. You won’t forget to make the speed change when the alarm sounds and “... -
Page 74: The Auxiliary Display
AUXILIARY display shows the ERROR (see page 58). Note: Prior to version 5.010 firmware, the display showed dashes (“– – – – – –”) unless the 798A was split. The Auxiliary Selecting on the TIME– –ODO switch lets you view an Auxiliary Odometer . -
Page 75: The "Delta" Counters
Calc Time is selected on the rotary switch. CHANGING When the 798A is powered up, the displays illuminate at their brightest setting. THE DISPLAY The display brightness can be adjusted to fit ambient lighting conditions. When the special BRIGHTNESS function position is chosen on the rotary switch, activating the “+ / –”... -
Page 76: The Remote Driver'smodule
Note: The error also visible in the main computer’s AUXILIARY display. See page 56. EEEE When you are outside the displayable range for the error, the 798A will show “ ” up to six hours early, or “ LLLL ” up to six hours late. If you are more than one hour early or ten minutes late, use the clock and the calculated time displays on the main computer to determine your error. -
Page 77: Details On The Error
“≡ :01 ≡”. This is to make negative † numbers more obvious. Details on Because the 798A counts time (both for the clock and the calculated time) in higher resolution than that which can be displayed, several counting peculiarities in the ERROR the ERROR display can be noted. -
Page 78: Adding An Offset Bias To The Error Display
(“≡ :00 ≡”) will be displayed for .9 seconds more. As an option, the 798A can be modified to show an error of zero for exactly 1 second when in the “negative numbers/units” format. The 798A accomplishes this by shifting all values of the error one half count toward zero. -
Page 79: The Driver's Auxiliary Display
), you can remotely switch between two of these choices. When option 7 is installed, an additional stereo input jack is present on the rear of the 798A. Use the “ R e m o t e A u x ”... -
Page 80: Operating Mode Indications
It’s better to make the correct adjustment the first time. Because of this potential for error, the 798A is programmed to alert you while it is operating in a non-standard mode or when you select certain rotary switch positions. To alert you, the 798A will either flash the entire display or just the decimal point (and colon, if appropriate) in the relevant rally parameter. -
Page 81: Transducer Failure Warning
798A operate normally. † You can adjust the length of time each beep sounds when the 798A is in park or reverse, or when the 798A is split. To do so, select ALARM on the rotary switch and momentarily actuate RESET . -
Page 82: Internal Battery Backup
Re-initializing the LED circuitry does not affect the numerical values of the data. Overall You can reset the 798A to factory default conditions if you wish. To do so, turn the instrument on while holding the RESET switch up. -
Page 83: Section 3 - Applications
These examples are not intended to answer all rally problems, but rather to stimulate your imagination in the ways the 798A can be used. As always, there are exceptions to any rule, so make an effort to understand the reason for each procedure. Most successful rallyists make up their own rally scenarios to prepare for “what if…”... - Page 84 APPLICATIONS Section 3 Checkpoint Upon arriving at a checkpoint, split the 798A at the timing line to freeze the CLOCK ODOMETER , and CALCULATED TIME displays. When the checkpoint workers give you Procedures your arrival time, verify that time with the split CLOCK display.
- Page 85 0.00, proceed along the course. By splitting at the in-line, you can change values within the 798A to what they should be at the in-line even though you will be past that point. Truncating (or casting) allows you to make a “retroactive CAST change”...
- Page 86 As for all legs of a rally, the 798A calculates the DIYC travel time using the distance you drive and the CASTs you enter. Since the calculated time is not dependent on actual driving time or speed, you can usually proceed along the course at your own pace.
- Page 87 APPLICATIONS Rebuilding a The 798A can be used by a rallymaster to confirm the travel time for each leg of a rally. Rather than employing a separate computer to calculate the ideal leg time, or even driving Leg of the the course to “measure”...
- Page 88 A d j u s t O RM function. If you can foresee that the official mileage will appear on the 798A before the reference is reached, there is another method for aligning the odometer and calculated time at the reference.
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Page 89: Sample Rally
Section 3 APPLICATIONS SAMPLE The first step toward becoming familiar with the 798A is often just a matter of activating its switches while working out rally problems. To that end, the following sample rally will RALLY exercise most features of the 798A. Although rather brief, the instructions are typical of many TSD rallies. - Page 90 APPLICATIONS Section 3 Step by Step When you arrive at the start of the rally, set the 798A clock to the official time and follow the procedures detailed earlier in At the Start of a Rally Critique Assuming that you’re going to use the Compute Factor feature, enter 13.19 as the...
- Page 91 “ARBY’S”. Note that the rallymaster has given an exact distance of 0.68 mile between the two signs. Let’s assume the 798A actually measured 0.683 mile. At a CAST of 1 mph, the travel time for 0.68 mile is 40.80 minutes; whereas for 0.683 mile, the travel time is 40.98 minutes.
- Page 92 CAST 48 the other third of the distance. Here’s one for the navigator. Don’t expect the 798A to do all the work for you! (Just in case you’re interested: Add together the minutes/mile equivalents for the three...
- Page 93 Your next step is to run an actual rally. But don’t expect to remember all the features of the 798A the first time you use it. There is always a learning curve associated with the operation of any sophisticated instrument such as the 798A. It is likely that you will make a few operational errors early on.
- Page 94 APPLICATIONS Section 3 This page intentionally left blank. TIMEWISE 798A...
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Page 95: Appendix A - Remote Inputs/Rear Panel
CAST rear panel inputs provide features that some rallyists find useful when adapting the 798A to their style of rallying. The use of these features is Control Inputs purely optional and is not required for normal operation of the instrument. - Page 96 During such rallies, the navigator may use a factor that is a little on the “high” side. The 798A will then accumulate mileage too fast. The navigator uses this “advance information” to warn the driver about impending turns or obstacles.
- Page 97 In such a case, just touching the outside of the 798A can cause a problem. If you get a shock when you touch the door frame as you exit your vehicle, you can be sure that you’re generating a very substantial static charge.
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Page 98: Appendix B - Preventing Problems
All connections must be as clean, secure, and direct as possible IMPORTANT! A proper connection to the ground lug on the rear of the 798A is extremely important. The wire used must be heavy gauge and as short as is practical. Make certain the chassis location you choose for this connection provides an easy path for draining static discharges and high frequency noise. - Page 99 AC and DC motors (blower motors and wiper motors are particularly nasty), etc. Electrical noise can cause the 798A to fail in a variety of ways. Some modes of failure are: meaningless information in the displays, erratic odometer measurements (usually too high), locked-up displays, reset of the computer to start-up status (although this is often caused by intermittent power), or a change in the counting rhythm of the clock.
- Page 100 There are two ways to stop the effects of RFI on the 798A. One is to protect the instrument from high levels of such interference. The other is to prevent the interference from being generated in the first place, or at least reduce its level.
- Page 101 The 798A will get warm. However, it should never get too hot to touch. If the 798A is so hot that you cannot keep your fingers on the metal, you are overheating the unit.
- Page 102 – 35°C (–22° F). Be forewarned that if you use the 798A on a rally where the weather gets very cold, keeping the instrument in an unheated vehicle overnight may result in loss of data. During overnight rest stops when the outside temperature can drop to less than –...
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Page 103: Appendix C - Odometer Input Specifications
Contact Pin assignments for the odometer transducer input modular jacks are listed below. Pin 1 is on the left when looking at the jacks on the rear of the 798A. The plug on the transducer cable Assignments will enter a jack with its flexible locking lever downward. - Page 104 IMPORTANT! * The 798A counts pulses from the transducer when the signal goes low. As shown in the table, this low level pulse needs to be valid for only 10 microseconds to be sensed by the computer. Be forewarned that odometer counting inaccuracies can occur when using a reed switch or other mechanical switching device in an odometer transducer.
- Page 105 ODOMETER INPUT SPECIFICATIONS Transducer Input At a vehicle speed of 120 mph the 798A can sense up to 30,000 pulses per mile (a factor of 003333) and keep up with incoming pulses. At this speed you will be receiving one pulse Limitations every millisecond.
- Page 106 Typically – 1.7 milliamps • (The input terminal is pulled to 5 volts within the 798A via a 3000 (typically) ohm resistor. The electronic speedometer drive circuitry must be able to sink this 1.7 milliamps when it outputs a low level signal.) Input frequency range: 0 to 640,000 Hz (up to 19,200,000 pulses per mile @ 120 mph) •...
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Page 107: Appendix D - Oscillator Adjustment
798A must be returned to Timewise for repair. (As a matter of interest, the clock in the 798A will be accurate to ± 0.01 minute after twelve hours if the oscillator is set to 230,400 Hz ± 3.2 Hz. When adjusted by Timewise, the oscillator frequency is initially set to 230,400 Hz ±... -
Page 108: Appendix E - Cleaning The 798A
798A from excessive dirt. One of the easiest ways to do this is to remove the 798A from your vehicle when you are not on a rally. In doing so, you will also remove a temptation from the prying eyes of thieves. -
Page 109: Appendix F - Materials List
MATERIALS Throughout this manual, there are references to components and materials used during installation of the 798A, as well as suggested spare parts and cleaning supplies required for LIST maintenance of the instrument. Here is a list of those items and suggested suppliers for them. -
Page 110: Appendix G - Technical Specifications
12.15" W x 3.75" H x 3" D with mounting bracket and knobs Main computer weight: Approximately 2 lb. 3 oz. Driver’s module size: 3.1" W x 2.1" H x 2.50" D Driver’s module weight: Approximately 5 oz. Driver’s module interconnect cable length: Approximately 3.5 ft. TIMEWISE 798A... -
Page 111: Appendix H - Minutes/Mile Table
1.17188 1.16959 1.16732 1.16505 1.16279 1.16054 1.15830 1.15607 1.15385 1.15163 1.14943 1.14723 1.14504 1.14286 1.14068 1.13852 1.13636 1.13422 1.13208 1.12994 1.12782 1.12570 1.12360 1.12150 1.11940 1.11732 1.11524 1.11317 1.11111 1.10906 1.10701 1.10497 1.10294 1.10092 1.09890 1.09689 1.09489 1.09290 TIMEWISE 798A... - Page 112 0.62370 0.62305 0.62241 0.62176 0.62112 0.62048 0.61983 0.61920 0.61856 0.61792 0.61728 0.61665 0.61602 0.61538 0.61475 0.61412 0.61350 0.61287 0.61224 0.61162 0.61100 0.61038 0.60976 0.60914 0.60852 0.60790 0.60729 0.60667 0.60606 0.60545 0.60484 0.60423 0.60362 0.60302 0.60241 0.60181 0.60120 0.60060 TIMEWISE 798A...
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Page 113: Appendix I 798A Options
The Timewise 798A is designed to be the most comprehensive class A rally computer possible. Within the limits of ease of use, the 798A provides all the features needed in the great majority of rally situations. Nevertheless, Timewise recognizes that many rallyists have their own style of rallying and often have a preconceived notion about the proper techniques of doing things. - Page 114 SHIFT , de-select Odo & Time . Method #2 Reset Main Odometer Depress and hold SHIFT , depress TRUNCATE . Truncate Main Odometer Depress TRUNCATE . Truncate Calculated Time Depress TRUNCATE . Adjust Calculated Time Select Calc Time , adjust calculated time. TIMEWISE 798A...
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Page 115: Appendix Jquick Reference Guide
Select LAST CAST , adjust ODOMETER display. Odometer Measurement Correct Last CAST On a 798A outfitted with Option 10, turn the rotary switch to Adjust ORM , Odometer Measurement w/ Select LAST CAST , adjust ODOMETER display. If the ORM is not to be Automatic ORM correction corrected, do not select Adjust ORM while making the adjustment. -
Page 116: Appendix K - Odds & Ends
Turn on the 798A with both SHIFT and TRUNCATE selected. Repeat to disable. “Delayed Truncate Action” Adjust “Speed” if unshifted Turn on the 798A with both SHIFT and the “– .001” position of the “+ / – .001” switch (and “Next Speed” if shifted) selected. Repeat to revert to factory default. -
Page 117: Index
28, 63, 98 manually setting the clock, 25 split warning resolution, 24 adjusting the tone length, 23, 63 when split, 24 upon activating CAST, 42, 63 synchronizing automatically to a Timewise checkpoint clock, 26 manually, 26 CLOCK display, 24 TIMEWISE 798A... - Page 118 60 Intelli-Sense™, 36, 63 removing the rightside triple minus sign, 59, 98 Italicized labels – shifted functions, 23 ERROR display, 23, 56, 58 Error Format function, 58 Jumper plug, odometer input, 35, 37 Error offset, enabling, 61, 98 TIMEWISE 798A...
- Page 119 Power requirements, 10 Odometer Factor, 32 Preset data, 52 Also see Factor. entering, 52 Odometer function, 29, 51 excluding, 52 Odometer input jumper plug, 35, 37 loading, 52 Odometer input pulse divider, 13, 34, 63, 87 Preset function, 52 TIMEWISE 798A...
- Page 120 25, 26 SPLIT switch, 23 used to adjust warning tone length, 23, 28 Stand-off mileage for odometer alarm, 55 Reset the 798A to factory default settings, 64, 98 Start-up procedure, 21 Reset the LED displays, 64, 98 Synchronizing the clock, 26 Resolution.
- Page 121 TRUNCATE function, 30, 41 Wiring enabling a one second delay, 30, 98 12 Volt Power, 10 Truncating Odometer input connector, 78, 85 calculated time, 31, 41 Remote Control Inputs, 77 calculated time minutes, 41 main odometer, 30, 41 TIMEWISE 798A...
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