Adept Rocketry - Instructions and Data Sheet
ES231 Series Low Current / High Current Electronic Stager™ with Memory
ST231 Series Low Current / High Current Timer with Memory
Copyright © 1989-2014, All Rights Reserved
The ES231/ST231 Series Stager/Timer is a series of Stagers and Timers that are capable of supplying very high current to igniters or deployment charges. The M in the Model designation stands for Memory. All six of the devices above include a nonvolatile memory in which to store the time setting. The value is permanent until it is easily reprogrammed to a different value.
Unlike a Timer, a Stager detects liftoff by first detecting acceleration, and then fires the next stage when it detects deceleration due to motor burnout. This is especially handy when the exact burn time of the first stage motor is not known, as with a hybrid motor. Also, an amount of coast time may be added before ignition of the next stage. A Stager can also be used to control airstart sequencing of motors.
A Timer arms at the first instant of liftoff and fires after a predetermined period of time. A Timer may be used for staging, airstarting motors, or for controlling parachute deployment at a given time after liftoff.
The ES231 Electronic Stager™ and the ST231 Timer are each offered in three different configurations with different current supplying capabilities. The versions capable of high current (designated H or LH) use an external battery to supply up to 12 amps of current for over two seconds, to fire virtually any type of igniters or deployment charges, depending on the type of load driving battery used, alkaline, nicad, etc. The designation L stands for low current; the device can fire (no external battery needed) flashbulbs or low-current electric matches such as the Davey Fire brand 28B or 28BR electric match. The designation LH stands for low current or high current. When just used for low current the device does not need an external battery. The small on-board battery along with the large electrolytic capacitor are used to fire the charge. When used for high current, an LH device requires use of an external battery. An H device (lowest cost) always requires use of an external battery even if used to fire only a low-current igniter or deployment charge.
A 12-volt lighter battery is used to keep the microprocessor system running glitch free during the times of heavy current demand to the igniter or deployment charge. On the L and LH models, current to a low-current load is actually supplied by the large electrolytic capacitor. The lighter battery is always used, even when an external battery is required.
Times are programmable to values in excess of 10 minutes in increments as fine as 1/100 second. The length of time in which the outputs remain energized is approximately 2.3 seconds. The programmed time setting is stored in nonvolatile memory, and is not affected when the device is turned off or when the battery is removed. The setting remains indefinitely until it is reprogrammed. Programming and testing is simple and quick.
This device uses Adept’s patented acceleration sensing system for simplicity and to insure safety. If acceleration and movement upward does not continue for at least 0.3 second, the timeout operation will not be enabled. The system cannot be set off accidentally by dropping, shaking, bumping, falling over, etc. With a Stager, time starts at the first moment of deceleration, following a valid liftoff. With a Timer, time starts from the first moment of liftoff.
NOTE 1: The circuitry on these electronic devices may be sensitive to noise and static when being held. Always handle the device by the edges when testing or installing to avoid touching any of the circuitry. Avoid carpeted floors and other sources of static electricity when handling and testing the device. Never store the device in a clear plastic bag; however, pink-colored or smoke-colored antistatic bags are acceptable. Do not use velcro to secure the device. Use care to keep the device clean and dry.
NOTE 2: The device must be installed only in a “clean area.” Electronic instrumentation is not compatible with the fumes and residue created by rocket motors and deployment charges. The Stager or Timer must be installed in an area that is totally sealed from rocket motors and charges. After passing wires through holes in bulkheads and such, seal them with epoxy or removable putty.
The procedures below may be followed as a tutorial.
Install a 12-volt alkaline lighter battery (GP-23A, Eveready Energizer No. A23, Radio Shack 23-144, etc.) in the battery holder. The spring end of the battery holder connects to the negative end of the battery. Remove the battery when not in use to avoid prolonged stress on the battery holder and possible long-term disfigurement of the battery holder.
Connect a CAB5-xx Series cable or special CAB5-12 cable (Adept CAB5BC Cable/Battery Clip Assembly, included) to the 5-pin connector on the upper end of the device.
POWERING UP THE STAGER OR TIMER
The device will power up when the ends of the BLACK wire and the BROWN wire are connected together. An On-Off switch may be used. When the device is powered up, it beeps every second to indicate normal operation and that it is now waiting for rocket liftoff. This is also the mode used for testing the device with or without a load connected. NOTE: when the device is turned off, it will continue to run for an additional 15 seconds or so until the large capacitor is discharged.
TESTING THE STAGER OR TIMER
The device is preprogrammed in the factory with a value of 5 seconds. To test the setting with no load connected, power up the device, and then close the Acceleration Switch for at least 0.3 second to simulate a valid liftoff. At the end of the time setting there will be a beep, then a pause, then the device returns to normal operation.
NOTE: the device is triggered when the Acceleration Switch remains closed for at least 0.3 second. It is virtually impossible for the device to fire due to dropping, shaking, or bouncing. Try it some time. However, when mounted in a rocket with the cable connector toward the nose of the rocket, and the Acceleration Switch toward the aft end of the rocket, the device will start when the rocket launches. The rocket motor must have a minimum thrust time of 0.3 second, and the rocket must accelerate with sufficient G force for a minimum of 0.3 second. This requirement is met by virtually all commercially available rocket motors that are used as recommended in rockets that have a maximum recommended weight. WARNING: don’t use this device in an experimental vehicle designed to operate with a slow takeoff. And don’t use motors that have an extremely short burn time.
The beep indicates when the output turns on, and after the pause, another beep indicates when the output turns back off.
PROGRAMMING THE ES231 / ST231
To program (permanently change) the time setting, the device must be powered up while the Acceleration Switch is held closed. This puts the device into programming mode, and programming is done via the Acceleration Switch. The Switch will be used as if it is a push button switch. The Switch state is normally open with the brass bar up against the battery holder. Push the brass bar toward the microswitch to close it, or close it via its chrome lever. But be careful not to damage the assembly.
A better way to close the switch is to use your right thumb to push up the short end of the brass bar. Place the device on a flat insulated surface with the cable connector away from you and the switch toward you. Hold it in place with your left forefinger on the battery. With your right thumb push the short end of the brass bar upward. This movement can be quick and precise. Practice this a few times.
Programming is done by closing the Acceleration Switch once to start the time setting, and again at the end of the desired time.
When the timer is powered up in programming mode, there will be a beep, followed by a long beep. Then the timer will start buzzing to indicate programming mode. You can use the second hand of a watch or clock to indicate times, or you can simply count seconds if real accurate settings are not important.
Programming the device takes a little practice at first. But after a few tries, it will be very quick and precise. Turn off the timer if not already off and wait for the beeping to stop. Close the Acceleration Switch, and turn on the Stager or Timer while the switch remains closed. You may release the switch as soon as you hear a beep. After the long beep the device will start buzzing. It will take two closures of the Switch to program the time setting, once at the beginning and again at the end. Watch the second hand of the clock for start and stop times.
You will close then release the Switch to start the time. There will be a beep, and the buzzing will continue. At the desired time, you will close and release again, and the buzzing stops. After a few seconds, the device will switch to normal mode, beeping once a second.
Example: to set the time to 10 seconds:
While the device is buzzing (and while watching the second hand on a clock), when the second hand reaches 12, close and release the Switch (beep). Then when the second hand reaches the 2, close and release again (buzzing stops). The setting is now 10 seconds and will remain this way forever until you change it again.
In a few seconds the device will be beeping once a second. You may now test the setting without a load connected. Close the Acceleration Switch for at least 0.3 second. In 10 seconds there will be a beep as the output turns on. Then in about three more seconds there will be another beep as the output turns back off and the device reenters normal operating mode again. Test again if you wish. If the device is an ST231 Timer, the 10 seconds will be from the first instant the Switch is closed. If the device is an ES231 Stager, the 10 seconds will start when the switch is first released, no matter how long it is held closed.
Special note for the ES231. The ES231 is a Stager, and a Stager must be capable of being programmed with coast times with the value zero. You may wish to fire the next stage immediately on burnout of the previous stage. To handle this requirement with the ES231, do the following. When programming coast times, always add 2 seconds to the time required for the coast time. If you want a coast time of 1 second, then program for 3 seconds. If you want a coast time of 4 seconds, then program for 6 seconds. If you want a coast time of zero, then program for 2 seconds or less. Any time programmed for 2 seconds or less fixes the coast time to zero.
There is no On-Off control switch or circuitry required for the external battery when one is used, but except for minimal current demand for continuity sensing, it cannot supply any current to the load until the device tells it to do so. If you wish to add a safety switch or disconnect in the external battery circuit, then connect it between the ORANGE wire and the Positive (Plus) Side of the external battery.
TEST THE ES231 / ST231 WITH REAL LOADS
The outputs may be tested with light bulbs, flashbulbs, electric matches, or Estes igniters. Light bulbs are the least expensive alternative for general purpose testing. But never assume that a particular type of igniter or charge or other device will work with your battery without first trying them. Warning: never install this device in a rocket without first testing its controlling outputs. Always test before each flight. Also, backup systems and/or instrument redundancy (use of two similar systems in the same rocket) are recommended.
When an igniter or deployment charge is connected to the cable, the single beeps of once a second, which indicates normal operation, change into double beeps to indicate continuity of the igniter or deployment charge.
When using an L version Stager or Timer, or an LH version with low-current charges or flashbulbs, the charge or flashbulb connects to the ORANGE wire and the YELLOW wire on a CAB5-xx cable. In this case the RED wire is not used, and you may remove it by pressing in the small metal tab.
When an H version or LH version unit is used with an external battery to fire high-current loads, the YELLOW wire is not used. One side of the high-current load connects to the ORANGE wire, and the other side to the Positive Side (+) of the Battery Clip, usually a red wire. The Negative Side of the battery (-), usually a black wire, but not the one on the cable, connects to the middle position on the cable connector where the RED wire usually goes. Connect the RED wire of the cable to the negative black lead of the battery clip, or snap the black wire end of the supplied battery clip into the middle position of the special CAB5-12 cable. And you may remove the YELLOW wire by pressing in the small metal tab. If you wish to add a safety switch or disconnect in the external battery circuit, then connect it between the ORANGE wire and the Positive (Plus) Side of the external battery.
If you wish to use a light bulb for low cost general testing, then use a low-current 6 to 12 volt bulb in place of a low-current igniter or flashbulb. It probably will just flash. In place of a high-current igniter, use a bulb with a voltage rating similar to the voltage of the external battery being used. It should stay turned on for the full 2.3 seconds. But always test at least once or twice with the same type of igniter that will be used in an actual flight. The proper way to test if a device can fire two igniters or deployment charges in parallel is to try it with three in parallel. If it can usually fire three, then it should always be able to fire just two.
MOUNTING AND INSTALLING
The device must be installed lengthwise in a rocket tube with the acceleration switch toward the bottom. It will fit as is in a 38 mm ID tube. In larger diameter tubes, the device may be mounted to a plate with #2 screws, standoffs, and hexnuts (do not enlarge the holes). Or it may be installed inside a 38 mm tube that is mounted to a plate. Whenever possible, support the lower end by mounting it against a bulkhead. The Stager or Timer must be installed in an area that is totally sealed from rocket motors and charges. After passing wires through holes in bulkheads and such, seal them with epoxy or removable putty.
If the Stager or Timer is used for igniting the second stage of a two-stage rocket, then it may be mounted in either stage. If it is mounted in the second stage, then the control wires will feed downward to the igniter in the same stage, and the second stage must carry the weight of the device. If the device is mounted in the first stage (booster stage), the control wires feed upward through some sort of disconnect connector and to the igniter of the second stage. In this case the second stage does not have to carry the weight of the device that lights its motor.
In a rocket with three or more stages (or three or more separate airstart ignition
sequences), the ignition controlling device may be mounted in the same stage, or in any higher
stage of the rocket in which the controlled motor is placed. Or it may be mounted in the stage
immediately below (where it will ignite the motor of the next stage above).
Adept Rocketry and Adept Instruments, Inc. warrant to the original purchaser that this
product is free of defective parts and workmanship and that it will remain in good working
order for a period of 90 days from the date of original purchase. This product will be
repaired or replaced within 90 days of purchase if it fails to operate as specified, if
returned by the original purchaser and if it has not been damaged or modified, or serviced by
anyone other than the manufacturer. Adept Rocketry and Adept Instruments, Inc., their owners,
employees, vendors and contractors shall not be liable for any special, incidental, or
consequential damages or for loss, damage or expense directly or indirectly arising from
customer’s or anyone’s use of or inability to use this device either separately or in
combination with other equipment, or for personal injury or loss or destruction of other
property, for experiment failure, or for any other cause. This device is sold as an
experimental accessory only, and due to the nature of experimental carriers such as rockets,
the possibility of failure can never be totally removed. It is up to the user, the
experimenter, to use good judgement and safe design practices and to properly pretest the
device for its intended performance in the intended vehicle, or reasonable facsimile of same,
under controlled conditions to gain reasonable belief that the device and vehicle will perform
in a safe manner, and to assure that all reasonable precautions are exercised to prevent
injury or damage to anyone or anything. WARNING: Do not use this device unless you
completely understand and agree with all of the above statements and conditions.
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ST231MLH Staging / Deployment Timer with Memory
Additional CAB5BC Cable/Battery Clip Assembly - Price: $5.49
CAB5-12 Cable Assembly, 5 leads, 12-inch length: $4.99
CAB5-24 Cable Assembly, 5 leads, 24-inch length: $6.25
CAB5-36 Cable Assembly, 5 leads, 36-inch length: $7.29
Additional GP-23A Alkaline Lighter Battery - Price: $2.25