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What is a Chrontrol?
Can you please summarize your product line?
Why do Chrontrol timers make the perfect solution for any application?
How do Chrontrol timers differ from the competition?
What is Interval? What is Cycle?
What is that "dash" between some holdays?
What is a "dry contact"?
What do you mean by "8 digital inputs"?
Why doesn't the p.m. dot stay lit?
Why does the L-series ignore program changes?
Why does the display blink?
Why is the display blank?
Why does a cycling program stop after only one cycle?
How about line filters?
How can I slow down the review speed on L series?
How can I eliminate unnecessary items to speed up the review?
How do I trigger from the opening of an input instead of the closing?
How do I get the ChronTrol to count down?
How do I set perpetual holidays?
The keyboard is locked - now what?
The relay won't turn on.
  Why does the date start at 3/1/99 on XT models?
How can I connect my computer to the L series Aux port?
Do I have to calibrate the ChronTrol?
Q: What is a Chrontrol?
A: ChronTrol Products are designed exclusively for time control of up to 16 separate power circuits. Thus, a ChronTrol installation is more suitable and less expensive than general purpose Programmable Logic Controllers (PLC's) and PC's. They are standard pre-engineered systems combining control electronics, power switching, and a specialized time-control oriented microprocessor program in a single, integrated package. Operation and maintenance are easier because routines for essentially any time control function are already built in. Power control scheduling procedures are similar to using an ATM.

    Time-of-Day routines control On-Off timing to the second by day of week, month or date and/or with holiday omissions. Up to 40 schedules, controlling 16 power circuits, can be set for selected days or times. Daylight/Standard time-adjust and Leap Year are automatic. External inputs initiate timing sequences; e.g., remotely turned on lights will automatically turn off at a specified time, or after a specified period. During a power outage, a back-up battery system maintains schedules and time-count. When power returns, scheduled circuits are energized all at once or in a delay sequence to minimize lighting and motor start-up power surges.

    Interval Timer routines are initiated by one of eight external inputs, a keyboard command or by a Time-of-Day schedule. An interval routine occurs only once when activated, or it can repeat to a preset cycle until stopped by an input or Time-of-day schedule.

    The L-Series models include additional features for building and energy management: latitude-corrected sunrise and sunset times, back-up battery condition display, display of last power outage, and cumulative time of past power outages.

    The 40 schedules for 16 power circuits are entered via a 24-key keyboard. In addition, schedules can be entered or checked over a serial data link or telephone modem from either the ChronTrol Remote Control Unit, or a PC. The ChronTrol Printer/Programmer accessory prints out existing schedules or reloads alternative schedules stored in its memory module.

    Categorically, ChronTrol is a Time Switch. You can program it to turn electricity on and off.

Q: Can you please summarize your product line?
A:   XT-Series Electronic Timers
• 2 to 16 separately controlled 115/240/277 VAC power circuits (6 to 20 amperes)
• 20 to 40 user-entered schedules to control separate or combined circuits
• Time-base and schedule-memory power-out protection
• Table-Top, Wall-mount or Rack-mount Models

    L-Series Energy and/or Building Management Timers
• All of the XT capabilities plus additional features directed to the needs of building management and control
• 60 user-entered schedules to control separate or combined circuits
• Expandable Wall-mount Model

    L-Series Accessories
• PRO60 Printer/Programmer
• T90 Remote Control Unit
• T50 Telephone Modem

Q: Why do Chrontrol timers make the perfect solution for any application?
A: Reliability
     ChronTrol Corporation has been manufacturing rugged and dependable microprocessor-based timing equipment since 1977.

Operational Capability

     ChronTrol timers are accurate to the second and can perform operations which previously required several electro-mechanical devices, cost thousands of dollars, or were impossible.

Easy to Program

     ChronTrol timers are capable of sophisticated on/off operations but require no special skills to program. The L Series model is completely self-prompting and error-checking. Both the L Series and XT Series can be programmed from your PC.

Load Rated Relays
     Unlike "low-voltage" systems, ChronTrol equipment provides 15-amp load rated relays standard.

Low Cost Per-Circuit

     ChronTrol is available at a retail cost of less than $90 per circuit (4-circuit XT model). ChronTrol delivers more features for a lower price than anyone else.

Technical Support

     Free technical, programming, and installation support is always available. Our toll-free 800 numbers provide a direct link to our factory service department.
Q: How do Chrontrol timers differ from the competition?
A:    The most exciting difference between a ChronTrol timer and the competition is that ChronTrol found a way to squeeze more speed out of modern digital electronics, so that ChronTrol timers are accurate to the second and can be set to the second, while the competitors are still struggling to get down to one minute resolution (which is a great improvement over the fifteen minute resolution you get from a motorized timer).
     Maybe they're happy with one minute resolution. Not that it costs more, but if you do in fact need circuits to switch at times that are not exactly minutes apart, ChronTrol is pretty much the only solution.
     Another exciting difference is ChronTrol's multiple circuit capability - you get as many as 16 independent 20-amp relays running from the same timer. The competition can't seem to fit more than two circuits into one of their boxes.
Q: What is Interval? What is Cycle?
A:     Interval timing is a revolution in the way ChronTrol handles timing. It used to be, years ago, that ChronTrol programs could only be set on a time-of-day basis. This meant you had to specify the exact time that you wanted your circuiits to turn on and off, which is okay in most cases because, after all, you know that the lights should be on from 8 in the morning until 5 at night. But it's not so great if you want to run something for a length of time. For example, to get an oven to turn on for the next 2 hours, you'd first have to check your watch to see that it's almost 3:15 p.m., then set your program to turn the oven on at 3:15 p.m. and off at 5:15 p.m. Unfortunately, the whole process might take you right past 3:15 p.m. so you'd have to do it again, this time shooting for 3:20 p.m. etc.

Interval timing changed all that. Instead of telling the ChronTrol to turn its circuits on and off at a particular time, you tell the ChronTrol to turn its ciruits on and off for a designated length of time. This duration of time is what we call an "interval."

The only remaining question is this: when does the interval begin? With no fixed point in time, an interval program just sits there and does nothing. You must start the interval program running by one of three methods: you can have another program start it at a specific time of day, or you can have one of your 8 digital inputs start it, or you can start it yourself with a keyboard command.

    Cycle, on the other hand, has been a feature of every ChronTrol since before the beginning. It is very simply the rate at which an event re-occurs. For example, if a circuit repeatedly turns on for 5 minutes and off for 3 minutes, it must be turning on every 8 minutes, so its Cycle Rate is 8 minutes. If you program a bell to turn on at 7 a.m. and cycle every 50 minutes, you'll find it turning on at 7:00, 7:50, 8:40, 9:30, etc. The following illustration shows the relationship between Interval and Cycle:

        It should be noted that Cycle Length must also be defined as the sum of the time              On and the time Off.

Q: What is that "dash" between some holdays?
A:     The dash between holidays indicates a linked holiday, in which every date between the two holidays is also treated as a holiday. This can be very useful if you intend to shut down a program for an extended length of time. You simply specify the start and end dates and the whole span becomes one long day off. You signify a linked holiday by pressing the colon key (:) twice instead of once between entries in Master Entry #4 (Holiday Setup).
Q: What is a "dry contact"?
A:     ChronTrol uses the term dry contact loosely to describe its 20-amp single-pole/single-throw (SPST) or single-pole/double-throw (SPDT) relay contacts. In this sense, "dry contact" is synonymous with the word "switch."

Strictly speaking, a dry contact is a switch which makes and breaks a connection in an open circuit, that is, a circuit which is already disconnected by a switch or other means somewhere else along the line. Since no current can flow in such a circuit, it is essentially "dry." The purpose of a dry contact is to prevent the other switch from completing the circuit. The dry contact has the capacity to conduct the current flow, but it is usually not rated to start or stop the current flow.

ChronTrol uses the term dry contact to emphasize that there is no output voltage from the ChronTrol relay. The relay is not pre-wired to any internal voltage source. That means you are free to use the relay to switch any electrical supply voltage or signal (up to 277VAC) that is wired to it.

Q: What do you mean by "8 digital inputs"?
A:    Inputs are another revolutionary idea introduced with the XT model, along with Interval Timing.

     Through an input, you can initiate a timed event that does not have a fixed position in real time. The input signal can come from anyone or anything anywhere, whether it's a guy pushing a doorbell, or a laboratory instrument indicating "operation complete," or a limit switch on an elevator indicating "end of travel." In the end, the signal boils down to a switch (or any conductor less than 1Kohm) making a short circuit between two points on the ChronTrol's input connector. The two points are:

          1. one of eight distinct, individually programmed inputs (electrically "pulled up" to +5 volts DC by a 10Kohm resistor) and
          2. a reference point (0 volts or signal ground) common to all 8 inputs.

     When the switch makes a short circuit between the two points, the input is "pulled down" from 5 volts to zero volts, and the input (if it is enabled, which is a whole nother issue) triggers whatever sequence of events it was programmed to control.

     When the switch opens up again, the input returns to 5 volts and is ready for another activation. This is what makes the input "digital": either the input is at 0 volts or at 5 volts.

     This is in contrast to an "analog" input which can make sense of a continuous range of voltages. For example, as a signal ranges from -10 volts to +10 volts DC on an analog input, it might elicit louder and louder music from an amplifier. An analog input may receive many types of continuous signals and also be of varying frequency or phase. Not so for a digital input - its sees the world only one way or the other, on or off, with no in between.

     That doesn't mean you can't drive a digital input with a slowly varying signal. As the input signal continues to rise and fall, at some point (roughly half way between 0 and 5 volts) it changes abruptly from on to off.

Q: Why doesn't the p.m. dot stay lit?
A:      The p.m. dot will light when the AM/PM key is pressed, but it will be ignored if your XT display format is showing 24-hour ("military") time instead of 12-hour (am/pm) time.

      You can flip-flop back and forth between the two display formats by hitting the TIME key followed by the ENTER key, and all the program settings you have made will change to the corresponding format. For instance, if you set a program to turn a circuit on at 8 a.m. and off at 3 p.m. and then change to 24-hour format, the on and off times will suddenly appear as 0800 hours and 1500 hours respectively. Now if you decide to change the off time to 4 p.m. you should either 1) put it in as 1600 hours or 2) change back to 12-hour am/pm format, because the AM/PM will be ignored and your entry will come out as 0400 hours (4 a.m.).

Q: Why does the L-series ignore program changes?
A:     If you choose sun-relative (a.k.a. "astro") programming, your programs will change from day to day according to the time of sunrise and sunset at your latitude. The choice to use sun-relative programming is made by hitting the AM/PM key once (for sunrise-relative) or twice (for sunset relative) when you are prompted for Cycle Rate. Once the choice is made, the ChronTrol L Series figures out the correct time for you. If you were trying to change this setting, the ChronTrol would simply overwrite it, giving the impression that it's ignoring you.

If you decide to change the program, we advise that you clear the program first. This will remove the sun-relative option. Subsequent program changes will no longer be ignored.

Q: Why does the display blink?
A:     Two reasons:

          1.   On XT models manufactured between 1991 and 1997, you must plug the timer into the wall before you connect its battery, because the timer tries to determine the AC line frequency as soon as it sees power, and if it sees battery power before AC power it starts running at top speed, in which a minute goes by in about 6 seconds accompanied by 10 rapid blinks, pause, 10 blinks, pause, etc. To correct this problem, unplug the ChronTrol and disconnect the battery for 2 minutes. Then plug the ChronTrol in first, then connect the battery.
          2.   The first ChronTrols ever made did blink once every second. There is no cure. Your ChronTrol is over 20 years old. Be glad it still blinks.

Q: Why is the display blank?
A:     You had a power failure and your battery was not up to the task. To correct this problem, unplug the ChronTrol and disconnect the battery for a few minutes. Then plug in the ChronTrol, then connect a fresh battery.
Q: Why does a cycling program stop after only one cycle?
A:     We've established that an interval program with no cycle occurs one time only, when called by an input, by another program, or by a keyboard command. A cycling program cycles, or repeats, until it is stopped by one of the above events.

The XT ChronTrol can use one program to control another. In the school bell application, for example, you see how numerous programs, with only a Turn On time, call an interval program throughout the day to ring a bell for a few seconds.

A program can even control itself, and this is where the trouble begins. Because when the program goes to turn off its circuits, it also turns itself off; hence, the effect of stopping after one cycle.

Correct this situation by carefully reviewing the program's control assignments and clear out any references the program makes to itself.

Q: How about line filters?
A:    We do not suggest the use of line filters with Chrontrol timers. Well-meaining people who have used line filters, thinking they'll just take that extra step to guarantee that the ChronTrol has a nice quiet place to work, usually cause more trouble than they prevent, the reason being that they probably aren't rated to pass along the kind of power your applicance needs. There are instances where something like an MOV on the line might be desirable.
Q: How can I slow down the review speed on L series?
A:     Hit any number key during the review process. The higher the number, the slower the review speed. You can pause the review altogether by hitting the NEXT key; resume reviewing by hitting the NEXT key again.
Q: How can I eliminate unnecessary items to speed up the review?
A:     You can set Master Entry #15 (Selective Review) to remove particular entries from the review stream, specifically those entries which weren't set in the first place. For example, if you set Program #1 with just an On time and Off time, you will be spared seeing the Skip Days, Cycle Rate, Duty Cycle On, and Duty Cycle Off roll out before you. In fact, their absence from the review is your assurance that they were not set accidentally. It also consumes less paper when you get a listing from your PRO60 Printer/Programmer.

On models built prior to 1985 this feature was accessed through Master Entry #69.

Q: How do I trigger from the opening of an input instead of the closing?
A:     XT models with 8 digital inputs ordinarily respond to the closing of the input, which is often designated the "leading edge" or "falling edge" of the input. Therefore, if you connect an input pin to one side of a switch, and connect the signal reference pin (called the "input common") to the other side of the switch, the input will be triggered when you close the switch. Depending on what you programmed that input to do, like turn a circut off or start an interval timer, all sorts of interesting things could occur.

     But what if you want to get action on the opening of the input instead of, or along with, the closing? Well, you can still have it. The 8 unused inputs (numbered 9 through 16) are internally connected to the inverse of inputs 1 through 8 respectively, so that when inputs 1-8 open, inputs 9-16 close. So whatever you set input #1 to do will occur when input #1 closes and whatever you set input #9 to do will occur when input #1 opens.

           See what the following program steps do:

Input #3 Triggerred when Input #3 closes

Input #11 Triggerred when Input #3 opens

Program #1  

     Circuit #1 turns on when Input #3 closes, and stays on until 5 seconds after Input #3 opens. This might be useful for changing a traffic signal shortly after a line of cars has finished a left turn.

Q: How do I get the ChronTrol to count down?
A:     Please follow the procedure located in your user manual. Click here to download the .pdf file.
Q: How do I set perpetual holidays?
A:     The dates of some holidays never change. Others, like Labor Day and Thanksgiving, change every year. Still others, like 4th of July and Memorial Day, vary erratically depending on whether or not they are near a weekend. We have a method to handle all 3 of these types of holidays.
Q: The keyboard is locked - now what?
A:     The first ChronTrols ever built had a fixed unlock code of 1 0 3, because a cat walking across the keyboard would most likely miss this sequence. The keyboard locks when you first plug the ChronTrol in, and after a power failure. You know the keyboard is locked because none of the keys respond when you push them. This includes the code keys 1 0 3. So it is not always possible to tell if you successfully unlocked the keyboard. Your best bet is to hit 1 0 3, then TIME and see if the display goes blank.

     There is no "back door" to the unlock code. Either it was put in deliberately, in which case you have to pay off the guy who has it (don't let this happen to you), or it was put in accidentally.

     Before you give up, consider the following:

     The keyboard beeps when you press each key, so if you're not getting a beep, the ChronTrol does not hear you. Keep in mind that when a key is held down it locks out all the other keys, so feel around and see if one of them is being held down. If a key has collapsed, you should send your timer in for factory repair. You can also get prompt temporary relief by lifting the key up with a piece of cellophane tape

     XT models do not require an unlock code, and they have none when first plugged in. To set one, you hit the LOCK key, which makes the display go blank, then enter a number (up to four digits), then hit the ENTER key. Study this table which shows what the LOCK key does:

Not Set (n/a) (*) makes the display go blank, waiting for you to enter a new unlock code.
Set Unlocked Locks the keyboard
Set Locked makes the display show 000, waiting for you to enter the unlock code.

     If the keyboard is locked and you enter the unlock code, then hitting:

ENTER unlocks the keyboard
LOCK takes you back to the (*) above

 and when you are at (*) above, you can always hit TIME, which leaves you once again with no unlock code.

     Of the 10,000 possible unlock codes, the one most likely to be set accidentally is 0000. So your first logical step for unlocking the keyboard if it's been locked accidenatlly is to hit LOCK LOCK. If the unlock code was 0000, the display will go blank. You should then immediately hit the TIME key, leaving no unlock code.
      If the display does not go blank, try LOCK 1 LOCK. If the display still doesn't go blank, try LOCK 2 LOCK

      If you are still unable to unlock the keyboard, simply pull the plug, disconnect the battery, wait a couple of minutes, then plug it back in with no battery.
Then all you have to do is re-program it from scratch.

Q: The relay won't turn on.
A:     Does the indicator light come on? If it does, that means something completely different than if it doesn't.

     If the indicator light comes on, that means that the electronics behind the ChronTrol are sound and the only problem you have is an electrical misconnection, or at worst a broken relay. But if the indicator doesn't come on, then a whole world of possibilities opens up, which our factory-trained technicians are prepared to straighten out. It could be anything from a programming mistake to a total computer meltdown. Your best bet is to pick up the phone and give us a call.

Q: Why does the date start at 3/1/99 on XT models?
A:     ChronTrol represents time internally in 24-hour format. Time runs from zero hours (midnight) to 23:59:59, then rolls back over to 00:00:00. (How the time is displayed is up to the user. In most cases, the time is displayed as 12-hour am-pm, just like a wall clock.)

     ChronTrol keeps the date internally in "ordinal date" format; the date runs from day 0 to day 364. Right off the bat, you can see that dates from March 1 onward have a different ordinal date in leap years.

     The ChronTrol XT model is required to do some pretty intensive calculations when it comes to cycles that extend past 24 hours. For instance, if you program a circuit to come on for two days out of every three, starting at 5 p.m. on February 28, will it go off at 5 p.m. on March 2? It helps to know if it's a leap year, because the circuit will actually go off on March 1 if it is.

      The reverse is just as cumbersome - if you say explicitly "Turn on Feb. 28, turn off Mar. 1, and repeat every 3 days," the circuits will do just that. But when will they come on again? On Mar. 2 or Mar. 3? You can't say for sure unless you know whether the program was set in a leap year or not. And if the program were set in a leap year, but after Feb. 29, does that mean the program would apply to the following (non-leap) year? You bet!

     The date of 3/1/99 is the internal represenation of the ChronTrol's date after initialization. Just as the timer also initializes time to 12:00 a.m. (this is the internal representation of 0000 hours which is the internal representation, how the data is stored internally).

Q: How can I connect my computer to the L series Aux port?
A:     If you're going over the phone lines, user part number T-50. If you're going direct, you need part number RS-AD.
Q: Do I have to calibrate the ChronTrol?
A:     Unlike the competition, ChronTrol gets its time base from the AC line frequency (50/60 Hz). It cannot be calibrated and does not need calibration.