Tempco TEC-410, Инструкция по эксплуатации

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19
3–6 Process Alarms
If Output 2 is designated as an “Alarm Output”, the alarm function, AL.FN can be setup for Process
Value High Alarm, PV.H.A or Process Value Low Alarm, PV.L.A. The process alarm sets an absolute trig-
ger level. When the process exceeds that absolute trigger level, an alarm occurs. The trigger level is
determined by the setting of the set point 2 value SP2 and the alarm hysteresis value AL.HY. The hys-
teresis value is introduced to avoid interference in a noisy environment. Normally, AL.HY can be set with
a minimum value 0.1.
The trigger levels for the process high alarm are SP2 and SP2-AL.HY.
The trigger levels for the process low alarm are SP2+AL.HY and SP2.
There are two types of alarm mode, AL.MD that can be selected.
They are Normal Alarm (NORM) and Latching Alarm (LATCH).
Normal Alarm: AL.MD=NORM
When the normal alarm is selected, the alarm output is de-energized in the non-alarm condition
and energized in an alarm condition.
Latching Alarm: AL.MD=LTCH
If the latching alarm is selected, once the alarm output is energized, it will remain unchanged even
if the alarm condition has been cleared, unless the power is shut off or the RESET
k ey (or remote
reset button) is pressed.
Failure Transfer: AL.FT=OFF or ON
If a S ensor Break or an A-D Failure occurs, the alarm output will be on or off according to the set-
ting of AL.FT.
E x amples:
SP2=200 AL.HY=10.0 AL.MD=NORM AL.FN=PV.H.A
200
190
200
190
200 200 200
190 190 190
ON
OFF
200
190
200
190
200 200
200
190
190
190
ON
S P2 = 200 AL.HY = 10.0
AL.MD = LTCH AL.FN = PV.H.A
Proce ss proceed s
Proce ss proceed s
Figure 3.3 Normal Process Alarm
Figure 3.4 Latching Process Alarm