| 摘要 |
A digital alarm system for monitoring a variable process signal utilizing a variable, digitally controlled alarm hysteresis capability. The system includes a means for establishing a preselected count level at which an alarm condition occurs. The preselected count level may be established in a high alarm or a low alarm state depending upon the process signal being monitored. Digital signals representative of the process variable are compared with the preset count level signals and upon a coincidence, an output signal is generated to provide alarm signals and also to reset the preselected count level signal to a second preselected count at a level which is a wide variation from the original preselected level so a relatively large change in the process signal occurs before the system is reset to its original alarm condition.
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