Honeywell DCP551 Mark ΙΙ User Manual page 83

Chapter 5. FUNCTIONS
5-34
Example 3:
Low temperature
sensor
Changeover
setting
A
Low tempe-
rature sensor
(1) When the high-temperature sensor senses that the temperature has risen to
changeover point A, the channel switches from the low-temperature to the high-
temperature sensor.
(2) When the high-temperature sensor senses that the temperature has risen above
the upper limit of the dead band and reached point B, the channel switches from
the high-temperature to the low-temperature sensor at changeover point C.
(3) No switching is performed at changeover point E when the high-temperature
sensor senses that the temperature has only dropped to point D and has not gone
below the upper limit of the dead band.
(4) When the high-temperature sensor senses that the temperature has reached point
F at the upper limit of the dead band, the channel switches from the high-temper-
ature to the low-temperature sensor at changeover point C.
Example 4:
Low temperature
sensor
Changeover
setting
A
Low tempe-
rature sensor
(1) When the high-temperature sensor senses that the temperature has risen to
changeover point A, the channel switches from the low-temperature to the high-
temperature sensor.
(2) When the high-temperature sensor senses that the temperature has risen above
the upper limit of the dead band and reached point B, the channel switches from
the high-temperature to the low-temperature sensor at changeover point C.
(3) When the high-temperature sensor senses that the temperature has dropped to
point D the lower limit of the dead band, the channel switches from the high-
temperature to the low-temperature sensor at changeover point E.
B
High tempe-
C
rature sensor
D
High tempe- Low tempe-
rature sensor rature sensor
B
High tempe-
C
rature sensor
D
High tempe- Low tempe-
rature sensor rature sensor
F
+
1/2 dead band
E
1/2 dead band
Ð
High tempe-
rature sensor
+
1/2 dead band
E
1/2 dead band
Ð
High tempe-
rature sensor