Sullair DHL-100 - Fail to Switch Alarm (Optional)

DHL HEATLESS REGENERATIVE DRYER SECTION 6
40
6.16 PRESSURE SWITCHES OF
“FAIL TO SWITCH ALARM”—
(OPTIONAL)
A pressure switch is installed on each tower (PSA
and PSB respectively) to enable the “FAIL TO
SWITCH ALARM” function of the SHDC-2100
device. The PSA pressure switch is closed when
tower A is under pressure and PSB is closed when
tower B is under pressure. The system is able to
detect an alarm condition if, for any reason, the flow
between the two towers was not switched or the
switching was not done correctly.
The “Fail to Switch alarm” function is enabled by
positioning the DIP U2 on ON (also refer to
Section
6.9
).
• Point 0 : PSA must already be closed,
whereas PSB must open in a maximum
time of 10 seconds.
• Point ½ : PSB must already be closed
whereas PSA must open in a maximum
time of 10 seconds.
• Point 1 = Point 0 (the cycles are repetitive).
Figure 6-10: Failure to Switch
Timing Sequence Diagram