| 摘要 |
PURPOSE:To permit alarm tracking after warning by outputting the direction of movement to a display device every time when a process input at every monitor input point movces by a preset constant at an upper or lower limit value in an increasing or decreasing direction. CONSTITUTION:A process variable at a monitor input point is detected by a detector S, whose detection signal S is converted into a digital signal PD through a process input device 1. This signal PD is converted 2 into an engineering unit numeral V, which is applied to a limit value comparing means 3. This limit value comparing means 3 has the preset upper and lower limit values and compares the input signal V with them to judge a normal or deviation state, outputting the result to a zone detecting means 4. This zone detecting means 4 detects at which preset constant section position the signal V is in the increasing or decreasing direction of the upper or lower limit value and displays the deviation from the upper or lower limit value and its direction on a display device 7 through an alarm tracking detecting means 5 and an output control means 6. |
