Adept RocketryDDCS25 Instructions and Data SheetDDCS25 Dual-Deployment Controller™ Two Versions:DDCS25 functions to 60,000 ft.DDCS25-100K functions to 100,000 ft.
Copyright © 1989-2011, All Rights Reserved DDCS25 Dual-Deployment Controller™ DDCS25-100K Dual-Deployment Controller™ DESCRIPTION The DDCS25 Dual-Deployment Controller™ is based on the ALTS25 Maximum Altitude Altimeter with Dual Deployment™. It is the same as the ALTS25 in all its functions except that it does not report altitude. It is less precisely calibrated than the ALTS25 and is therefore lower in price. One of its primary uses is as a redundant backup for the ALTS25 (they both fly in the same vehicle). Or the DDCS25 may be used as a primary device to control Dual Deployment™ in a flight when the actual altitude attained is not important. The DDCS25 has two altitude controlled deployment switches that are typically used to fire deployment charges, based on altitude. The first charge fires when the rocket reaches its maximum altitude (apogee), and the second charge fires when the rocket descends to 1800, 1200, 900, 600, or 300 feet above ground, or two seconds after apogee, or at 150 feet below apogee (user selectable). One common usage is to deploy a main parachute at apogee by using only the first output. However, the most typical usage is to deploy a drogue chute or streamer first, then to deploy a main parachute when the rocket descends to a user selected altitude above ground (Dual Deployment™), in order to avoid significant drifting due to wind. Dual Deployment™ was invented by Adept Rocketry in 1990 when the term was copyrighted and trade marked. The term Dual Deployment™ remains the sole property of Adept Rocketry. This device is used in rockets that will reach at least 300 feet altitude. Either or both deployment switches may be used. The DDCS25 may be used in any rocket configuration including multistage rockets, in which case the deployment control for a particular stage can be handled by placing the device in the particular stage of interest. Or individual DDCS25 units (or other altimeter devices) may be placed in each stage of interest to handle deployment for each stage. The DDCS25 functions to a maximum of 60,000 feet above sea level. The DDCS25-100K is an extended version that functions to 100,000 feet. The DDCS25 measures 1.4” wide by .6” thick by 3” long. It fits inside a tube with a minimum ID of 1.5” (38 mm). It will also fit on either side of a center divider inside a 54 mm ID bay 3” long. The device weighs only 1 ounce, including the battery. It uses a 12-volt alkaline lighter battery with a battery life up to 6 hours, so you need not be concerned about how long your rocket sits on the launchpad after the unit is powered up. The DDCS25 is a totally stand-alone device including the battery holder, arming mechanism, and current source for firing deployment charges. Nothing more is required except for the wires (interconnect cable) that connect to the On-Off switch and to the deployment charges. The altimeter device uses a custom absolute pressure device to precisely measure altitude values up to 100,000 feet in one-foot increments. It uses a 18-bit logarithmic analog-to-digital converter to precisely (one-foot resolution) measure the nonlinear pressure versus altitude relationship over this large altitude range. Once powered up, the DDCS25 reports that neither, or one or both deployment charges has continuity. It also constantly measures the ground-level altitude and waits for a quick 300-foot change upward. The first deployment switch fires at the very moment when the rocket reaches the maximum altitude. The second switch fires when the descending altitude reaches either 1800, 1200, 900, 600, or 300 feet above the ground, (or two seconds after apogee, or 150 feet below apogee) as preset by the user. Note: the DDCS25 cannot be used for, and will not function for, maximum altitudes less than 300 feet. SPECIFICATIONS
TESTING AND USING THE DDCS25 NOTE 1: The precision amplifier circuitry and continuity sensing circuitry on the DDCS25 may be sensitive to noise and static when being held. A 10-second silent time following power up gives time to get your hands off the unit before it starts taking readings. 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; clear plastic bags are prone to static buildup and discharge. However, pink-colored or smoke-colored antistatic bags are ideal, because they are chemically treated to prevent static buildup. Storage in a small cardboard box, or wrapped in a paper towel inside a clear plastic bag is acceptable. Do not use Velcro to secure the device, as Velcro is a substantial source for unwanted static discharge. The DDCS25 is a super precision instrument. Use care to keep the device clean and dry. NOTE 2: This 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 DDCS25 must be installed in an area that is totally sealed from motors and charges. After passing wires through holes in bulkheads and such, seal them with epoxy or removable putty. 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 an Adept CAB6L-xx series interconnect cable to the 6-pin connector on the DDCS25. The BLACK and BROWN wires enable power to the altimeter device when they are connected together. They may be connected to an On-Off switch. The RED and ORANGE wires connect to the first deployment charge, the one that fires at apogee. The YELLOW and GREEN wires connect to the second deployment charge, the one that fires during descent as selected by the user. To turn the unit on, connect the BLACK wire and the BROWN wire together. Typically these wires will connect to a normally-open On-Off switch or other device. Or the two wires simply may be twisted together. The unit sounds out a long pulsating beep when powered up, to indicate proper operation. After ten seconds of silence the unit starts beeping once a second to indicate that it is now taking altitude readings and is waiting for liftoff. If flashbulbs (or low-current electric matches at a safe distance) are connected (don’t connect anything quite yet), the beeping changes from a single beep to other beeping patterns to indicate continuity of the deployment charges. A single beep indicates proper operation with no deployment charges connected. A double beep indicates continuity of only the first output or first deployment charge, the one that fires at apogee (maximum altitude). A triple beep indicates continuity of only the second output or second deployment charge, the one that fires during descent as selected by the user. Four beeps repeating indicates that both deployment charges have continuity. SETTING THE SECOND OUTPUT VALUE When viewing the front of the DDCS25 (with the cable connector at
the top, and the battery holder near the bottom), a four-pin square connector is located
below the right end of the battery holder. When no jumpers are installed on the connector,
the default altitude setting is 600 feet above ground. The second deployment charge will
fire during descent at 600 feet. When a single shorting jumper (Radio Shack Cat. No.
276-1512 or equivalent) is installed horizontally on the lower two pins only, the setting is
300 feet. When a single jumper is installed horizontally on the upper two pins only, the
setting is 900 feet. When two jumpers are installed horizontally, on both the lower two
pins, and on the upper two pins, the setting is 1200 feet.
Jumpers also may be installed vertically on the four-pin square connector. When a single
jumper is installed vertically on the left two pins only, the setting is 1800 feet above
ground. The second deployment charge will fire during descent at 1800 feet.
When a single jumper is installed vertically on the right two pins only, the second
deployment charge will fire two seconds after apogee (two seconds after the first
charge fires). With this setting it is possible to use the second output as a backup for the
first charge. With this setting it is possible to create an apogee deployment sequence that
is implemented with two timed steps.
When two jumpers are installed vertically, on both the left two pins, and on the two
right pins, the second deployment charge will fire after apogee during descent at 150
feet below apogee. One of the many possibilities for this setting is to click a camera
after the rocket's descent has stabilized.
To simulate rocket liftoff it is necessary to pull a vacuum on the altimeter while
it is inside a sealed chamber. You need only hold the vacuum for a few seconds, then slowly
release. However, the best method is to put the whole device (including wires and flashbulbs
or small light bulbs, for testing the output switches) inside a small wide-mouth juice
bottle, and pull a vacuum on the bottle (or you may use an Adept VCK2 Vacuum Chamber - see VCK2 Vacuum Chamber and VCK2 Instructions).
It is easy to simulate rocket flights to altitudes of several thousand feet. Slowly pull the
vacuum, then slowly release the vacuum. As the vacuum (altitude) increases, the DDCS25 will
BOOP to indicate that 300 feet has been reached (liftoff). Then when the altitude starts its
descent (vacuum is being released), a BEEP will indicate that the maximum altitude was
reached, and this is when the first output (apogee) fires. When the simulated altitude falls
to the user selected altitude above the original ground level, there will be a long BEEP,
and this is when the second output fires. Warning: never install this device in a rocket without first testing its controlling
outputs. Always test before each flight. Also, backup deployment systems and/or
instrument redundancy (use of two similar systems in the same rocket) are highly
recommended. NOTES ON MOUNTING AND INSTALLING The DDCS25 may be installed lengthwise in a small-diameter rocket
tube. It will fit lengthwise in a 38 mm ID tube. Also, it may be mounted lengthwise on
either side of a center plate inside a 54 mm tube. In larger tubes it may be mounted flat
against a bulkhead. The mounting holes are .090 inch diameter for #2 hardware. Use #2
screws, standoffs, and hexnuts when mounting the altimeter to a plate or bulkhead. Do not
enlarge the mounting holes, and do not use Velcro.
An Altimeter must be installed in a "sealed" chamber with a vent or vents to
the outside. A sealed bulkhead below the altimeter chamber is necessary to avoid the strong
vacuum caused by the aft end of a rocket during flight. Any leakage around the motor mount
or in other areas at the aft end of the rocket will allow the strong vacuum to be partially
felt inside the rocket body. In this case an altimeter could incorrectly indicate and record
an altitude that is far higher than reality. A sealed bulkhead above the altimeter chamber is necessary to avoid any pressure
fluctuations that may be created at the nose end of the rocket. If the front of the payload
section slip fits to another section such as a nosecone, then the fit must be as free as
possible from turbulence. A breathing hole or vent (also known as a static port) to the outside of the rocket must
be in an area where there are no obstacles above it that can cause turbulent air flow over
the vent hole. Do not allow screws, ornamental objects, or anything that protrudes out from
the rocket body to be in line with and forward of a vent hole. The vent must be neat and
burr free and on an outside surface that is smooth and vertical where airflow is smooth
without turbulence. Some rocketeers use multiple static ports (vent holes) instead of just one. Very strong
wind blowing directly on a single static port could affect the altimeter. Multiple ports
evenly spaced around the rocket tube may help cancel the effects of strong wind, the
pressure effects of a non-stable liftoff, or the pressure effects that occur due to flipping
and spinning after deployment. If you wish to use multiple ports, then use three or four. Never
use two. Ports must be the same size and evenly spaced in line around the tube.
The general guideline for choosing port size is to use one 1/4 inch diameter vent
hole (or equivalent area, if multiple holes are used) per 100 cubic inches of volume in the
altimeter chamber. For instance, An eight-inch long four-inch diameter tube has a volume of
about 100 cubic inches. Use one 1/4 inch port, or three or four 1/8 inch ports evenly spaced
around the tube. An altimeter chamber two inches in diameter and eight inches long (25 cubic
inches) needs one 1/8 inch vent hole or three or four 1/16 inch vent holes. Try to keep hole
sizes within -50% or +100% of the general guideline. Do not make the holes too small, and especially
do not make them too large. In general, the vent holes need never be smaller than 1/32
inch. Also, the vent hole diameter need never be less than the thickness of the body tube. Adept Rocketry completed the research on static port sizes in 1990. The information
provided here has remained the industry standard ever since those early years. When possible, vent holes should be a minimum of four body diameters below the junction
of the nosecone with the rocket body. This is necessary with high performance (high speed)
rockets. The tremendous pressure on the nosecone leeches down the rocket body as much as
three or four body diameters before it dissipates. However, with lower speed rockets, the
"minimum of four body diameters" rule may be reduced to one or two. LIMITED WARRANTY AND DISCLAIMER
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 judgment 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, agree with, and
accept all of the above statements and conditions. DDCS25 Dual-Deployment Controller™ DDCS25-100K Dual-Deployment Controller™ ADDITIONAL ACCESSORIES
Additional CAB6L-24 Additional GP-23A Shorting Jumpers are used to connect two connecter pins together in order to turn on the
power for some of the Adept devices. Shorting Jumpers are also used on some devices to
program certain values or functions. They are used on the DDCS25 to program the value for
the Second Output Function, the output that fires the Deployment Charge for the Main
Parachute.
Shorting Jumpers Electronic Instrumentation is not compatible with the fumes and residue created by
rocket motors and deployment charges. Seal holes and gaps in bulkheads and such with
epoxy or removable putty.
The perfect mate for the DDCS25 when used in a dual redundancy backup system is the
ALTS25. The ALTS25 would function as the primary device to measure altitude and to control
Dual Deployment™. The DDCS25 would function as the redundant backup device to also control
Dual Deployment™. The ALTS25 measures altitude to 25,000 feet with deployment that
functions to 60,000 feet. The ALTS25-60K extended version measures altitude to 60,000 feet
with deployment that functions to 100,000 feet.
ALTS25 Maximum Altitude Altimeter with
Dual Deployment™ ALTS25-60K Maximum Altitude Altimeter
with Dual Deployment™ www.adeptrocketry.com 11/30/11 |
