FIG. 8: DOUBLE BREAK WIRING FOR FREE EGRESS (SPDT SWITCH)
| NC | C | | |
| NO | | + | FAIL SAFE |
CPU BOARD | | |
SPDT | | | ELECTRIC |
| MOV | |
| SWITCH | | LOCK |
REX | NC1 C1 | | |
| | |
WHEN THE EXIT SWITCH IS ACTIVATED, THE NC CONTACTS OPEN WHICH RELEASES THE FAIL SAFE LOCK. AT THE SAME TIME, THE NO CONTACT DIRECTLY ACTIVATES THE REX INPUT. THIS DEENERGIZES THE LOCK CONTROL RELAY WHICH RELEASES THE LOCK "A SECOND TIME" FOR THE AMOUNT OF TIME THAT HAS BEEN PROGRAMMED. IF THE DK-26 SUFFERS A FAILURE, THE EXIT SWITCH CAN STILL RELEASE THE LOCK FOR SAFETY.
4. PROGRAMMING
The DK-26 has ten numbered keys and a bell key which is used for several functions. Each of these keys is read separately by the unit, so the DK-26 is a true 11 digit access device. This provides excellent security against a code being guessed. Also, the DK-26 employs non-volatile EEPROM memory so that all programming is retained in a power failure.
Another point to note is that all DK-26 codes will operate the unit when their sequence is entered regardless if other incorrect digits were entered before. For instance, if the correct code is 2-2-6-7, the unit will operate if 8-2-2-6-7 is entered. An exception to this is if a total of 16 wrong digits are entered. In that case, an alarm function comes into play. The keypad will lock itself out for 30 seconds and the beeper will sound continuously. This feature discourages attempts to guess the code.
Before learning all programming options for the DK-26, you should decide how you want the unit to be used. Then learn only the appropriate programming for that use. This simplifies the task of operating the unit and cuts down on unneeded service calls.
The programming questions to ask are: do you want a “fixed” code that will either never be changed or changed only rarely? Or do you want regular code changes from the keypad? This issue depends on the amount of security called for in the application. Finally, do you want multiple codes? The DK-26 supports 59. The purpose of multiple codes is to assign different codes to individuals or groups. Then if a code needs to be changed, the other individuals or groups need not go to the trouble of learning a new code. This is a convenience issue.
4.1 FIXED PROGRAMMING
Employ fixed programming in a situation where the end user is not likely to ever change the code, or at least that changes would be rare. Fixed programming can be used in lower security
