Add-A-Stop Combination Action Installation Guide Board Version 2.0 Program Version 2.2 11 March 2002 Etna Instruments ===== INTRODUCTION ===== The Etna Instruments "Add-A-Stop" is a miniature combination action that provides support for a single stop controlled via 16 pistons, an optional reversible piston , a CANCEL button, and an optional SETTER button. The Add-A-Stop also supports the "hold and set" method of setting stops onto pistons. The Add-A-Stop consists of a small circuit board, about 3" by 6", that can be mounted within the organ console or chamber in any position; four corner holes are provided, suitable for #6 screws. The board should be protected from accidental damage but requires no special cooling or other environmental conditions. The system uses a small microcontroller to perform its work; this is the large integrated circuit near the middle of the board. The stop's status for each piston is stored in a non-volatile memory device that requires no battery or other power source when the organ is turned off. In the following description, we assume the board is arranged so that the terminals are across the bottom and the title "Add-A-Stop" can be read from left to right. ===== INPUTS AND OUTPUTS ===== The Add-A-Stop is fitted with a number of input and output connection points. These may be solder pads, screw terminal blocks, or "clamp cage" terminal blocks. Starting at the right side and moving left, they should be connected as follows: +12 : The positive side of the organ's DC power supply (12-20vdc). Gnd : The negative (ground) side of the DC power supply. OFF : The stop's OFF magnet. ON : The stop's ON magnet. STP : The stop's switch contact. C : The CANCEL button. S : The optional SETTER button or a wire to +12. R : A reversible piston. 1 : Piston #1. 2 : Piston #2. ... : ... 16 : Piston #16. All of the signal inputs (STP, C, S, R, 1, ... 16) are positive when active. These inputs are protected against reversed polarity and are fitted with pull-down resistors so that they will be "off" if left disconnected. You should run wires from the appropriate buttons and pistons to these input positions, in effect wiring the Add-A-Stop in parallel with the existing combination action. The OFF and ON outputs can be either positive or negative, depending upon what type of high-current driver chip is installed. A pair of solid-state fuses ("F1" and "F2") protects the OFF and ON outputs. These are rated to carry .5 amps continuously and will reset themselves when an over-current condition is removed. If you do not want to use these fuses, you can simply solder a jumper wire across each one's leads. The first four connections (+12, Gnd, OFF, and ON) should be made with sufficiently heavy-gauge wire to carry the magnet drive current, while the others can be 24ga or 26ga, as is normal for organ control circuits. If your board is fitted with the Pheonix Contact "clamp cage" connectors, you will need a small screwdriver or other implement that you can insert into the slot above the wire entry position. As you raise the tool's handle, the tool's tip will press against the clamp spring, thereby opening the jaws that will grasp the wire. These connectors are designed to work with wire from 12ga to 28ga. They are not "insulation displacement" connectors, and so you must strip the insulation from the end of the wire. If your board is fitted with screw terminal blocks, then you will need a small screwdriver that fits the screws. If your board has no connectors, then you can install your own or you can solder wires directly to the pads. Radio Shack stores carry a small terminal block that works well; it is their part number 276-1388A and consists of 4 2-postion blocks that interlock into a single 8-position unit. You will need three of these to provide for all 24 connection positions. If you prefer to solder directly to the pads, we suggest you first "tin" the pads with just a little bit of solder (and as little flux as possible). You should also fill in the hole nearest the edge, tinning it from both sides. When you attach the wires, you can bend the ends so that they enter the second hole on each pad; again, a minimum of solder should be applied. For the +12, GND, OFF, and ON pads, we suggest you also touch the soldering iron to the wire on the bottom side of the board where it comes through the second hole, since these are high-current connections and the board layout carries those connections on the bottom side. ===== CONFIGURATION JUMPERS ===== The Add-A-Stop contains 4 pairs of pins onto which you can install little shorting jumper blocks, also called "shunts". These pins are there to let you configure certain aspects of the Add-A-Stop. They are located "above" the processor and are labelled "A" at one end and "D" at the other; "B" and "C" are the intermediate pairs. In each case, the two pins in a pair are arranged in a "vertical" fashion; to install a jumper, place a shorting block so that it connects the two pins of that letter: A B C D A B C D Positions A and B let you specify how long the Add-A-Stop should fire the ON and OFF magnets to move the stop. This table shows you the jumpers and the resulting time in milliseconds: ---- ---- 150 milliseconds (Standard) -B-- -B-- 100 milliseconds (Faster) A--- A--- 250 milliseconds (Slower) AB-- AB-- 400 milliseconds (Very slow!) The standard value, with no jumpers installed, is 150 milliseconds, and that should be a good balance between reliability and repetition. Some stop action units work perfectly fine when fired for 150 milliseconds, but some might require a longer firing pulse. If yours seems to "slip" or "bounce" when fired for 150 milliseconds, you can install jumper "A" to lengthen the firing pulse. Only the most sluggish stop action units should require the very long pulse produced when both "A" and "B" are installed. If you find the standard pulse too slow, you can install just jumper "B" to make it a bit shorter. Position "C" can be used in conjunction with position "D" to let you adjust the Add-A-Stop so that it fires the ON and OFF magnets so as to match the speed of the other stops in the console. The following diagram shows how to position the jumper block so that it connects the "C" and "D" pins: ---- --CD (The block is next to and parallel to the big processor chip.) This is useful, for example, if you have added a stop action unit that is faster than the existing combination action; with this jumper you can teach the Add-A-Stop to delay firing its magnets. When this jumper is installed, CANCEL, piston #1 and the Reversible will operate normally and the other piston inputs will be used to select a delay time. The formula for that delay, in milliseconds, is 10 * (piston# - 2), so piston #2 provides for no delay and piston #16 provides for 140 milliseconds of delay. The last value you select is saved away in non-volatile memory and will be used whenever the Add-A-Stop is in operation. You can try various values and see what works best. You should then remove the jumper so that the Add-A-Stop will operate normally. Position "D" can be installed to disable the use of the "hold and set" method of setting pistons. Normally, both "hold and set" and the SETTER button are available for setting pistons. If your console has an existing "hold and set" system, then you can simply leave the "S" input unconnected. If your console has a SETTER button, then you might want to install jumper "D" to save the organist from possible confusion. With none of the jumper blocks installed, the Add-A-Stop will fire the ON and OFF magnets for 150 milliseconds as soon as a piston is pressed and both SETTER and "hold and set" will be available. For your convenience, we have included several jumper blocks. They are positioned such that they are *not* actually installed as part of the circuitry. You may remove them if you like. If you need additional jumpers, they are available as a standard item at many electronics supply houses, including Radio Shack (part number 276-1512, for a package of 10). ===== INDICATORS ===== The Add-A-Stop has Red, Yellow, and Green LEDs, located at the left end of the board. These LEDs will show you what the system is doing and which inputs are turned on. Red: This LED is lit while the OFF magnet is being fired or when the SET button is pressed. It is also lit when the +12v supply is too low, as when the organ is being turned off. Yellow: This LED is lit when any of the 16 pistons (or R) is pressed. Green: This LED is lit while the ON magnet is being fired or when the CANCEL button is pressed. It is also lit while data is being stored into the non-volatile memory unit (for example, when you set a combination). When nothing else is happening, it blinks every few seconds, just to show that the Add-A-Stop is up and running. You can use these LEDs to show that the wiring from CANCEL, SET, and the pistons is correct. You can also use them to see when the Add-A-Stop is firing the magnets. In addition, the LEDs also indicate various conditions when the Add-A-Stop is powered on: Red and Yellow and Green: The Add-A-Stop processor is starting up. Yellow and Green: The processor is reading from the non-volatile memory unit. Green: The system is ready to be used. Red and blinking Yellow: There is a system error! ===== MISCELLANEOUS ===== There is little push button labelled "Reset" near the upper right corner of the board. This button will reset the processor, just as when the power is turned on. Since the jumper positions are checked when the system starts running, you can use this button to force the system to take a new look at the jumpers without having to turn the entire organ off and on again. When the +12 input falls, the processor will take notice and will avoid writing into the non-volatile memory unit. This should prevent any errors should the organ get turned off while a piston is being set. The Add-A-Stop can generate either positive or negative (ground) outputs to fire the ON and OFF magnets. For positive outputs, socket "U5" (at the lower right corner) will contain a UDN2981 or TD62783. These are high-current "source" drivers that are capable of producing a maximum of about 350 milliamps per position. On the Add-A-Stop, three positions are wired in parallel for each of the ON and OFF outputs; that should provide sufficient current for any standard organ stop action unit. For negative (grounded) outputs, socket "U5" will contain a ULN2003 high-current "sink" driver that is capable of about 500 milliamps per position. Again, 3 positions are wired in parallel for each of the ON and OFF outputs. Note that the ULN2003 must be placed at the right end of the "U5" socket, leaving two socket positions empty! If you are using stop action units like the Reisner "C3", where the unit's frame is connected to the common magnet wires and serves as the feed for the stop switch, then you will probably have to use a negative driver. The inputs are all routed through a network of resistors and capacitors to provide protection against reversed polarity and against voltage spikes that might be generated by high-current signals on other wires. The non-volatile memory unit is an "I2C serial EEPROM" that is rated for 1 million writes and a 100 year data retention period. We hope that will be sufficient! The processor, a very common "8051" type microcontroller, is running at a very slow clock speed, about 8KHz (yes, "K", not "M"), so it should be very immune to electrical disturbances and will also consume very little current. If you need to support more than 16 pistons, you can use multiple Add-A-Stop units, wiring the ON and OFF outputs and the "K" inputs in parallel. If you need to support more than 1 stop, you can use multiple Add-A-Stop units, wiring the pistons, CANCEL, and SETTER inputs in parallel. Theoretically, you could build any size combination action this way, but at some point it will not be economical to do so! ===== SPECIAL FEATURES ===== The Add-A-Stop includes some special features that were included to make it easier to build and test the units. They are probably of little interest to an installer, but here they are, anyway, in case you are curious! The first feature is a means for totally erasing the non-volatile memory. To do that, connect jumper pins A and D with a wire. These are the pins in each pair nearer to the processor, and you cannot connect them with the usual little shorting blocks. If you turn on the Add-A-Stop or press its RESET button with those two pins connected, then the system will erase its memory before starting up. The Yellow LED will be turned on while the memory is being erased. The second feature is a more complex self-test routine. To run this test, connect jumper pins A and B (using a shorting block "sideways") and also turn on the CANCEL input. Now power-on the Add-A-Stop or press its RESET button. The system will see the CANCEL input and the A+B connection and will enter the self-test routine. In this routine, the Green LED will be lit for SET, the Yellow LED will bit lit for the Reversible, and the Red LED will be lit for CANCEL. If the stop is turned on, then all 3 LEDs will be lit. For each of the 16 pistons, the Yellow LED will blink a number of times equal to the piston's number. While this isn't a terribly interesting test, it does let us exercise all of the LEDs and all of the inputs. To test the magnet firing circuits, start up the Add-A-Stop in the normal way and use the Reversible input to toggle the stop. ===== WARRANTY ===== Etna Instruments provides a 5-year warantee on the materials, workmanship, and internal program logic of the Add-A-Stop when used for its intended purpose and in undamaged condition. Raymond L. Chace Etna Instruments Ithaca, New York 14850 rlc1@etnainstruments.com www.etnainstruments.com