Pub. No. OM-A-10E — April 2004
9
3.
LOW PRESSURE:
All heated regenerative dryers
are supplied with Low Pressure Switch Inhibit. When
the low pressure is detected, all timing functions stop
and all loads are de-energized. The red LED on the
remote I/O module will light up and “LOW
PRESSURE” will be displayed on the LCD screen.
This function will put dryer operation in the fail-safe
mode. Both the inlet valves will fail OPEN and the
purge valves will fail CLOSED. As soon as the
pressure is restored, the normal functions will
resume. The Low Pressure inhibit is set to operate
when the pressure in the dryer drops to 50 PSIG
(3.4 BarG).
4.
RELAY OUTPUTS (DRY CONTACTS):
There are
two relay outputs for remote annunciation. The
output is normally open rated for 10 AMPS resistive
at 125VAC, 5 AMPS resistive at 30VDC. The outputs
are for the inhibit Failure to Switch and High
Humidity. If one or both inhibits are made, the relays
will be energized and the LED on the remote I/O will
light up.
HEATER TEMPERATURE CONTROL
1.
THERMOCOUPLE INPUTS (3):
T.C.1 – Heater temperature.
T.C.2 – Left Tower desiccant bed temperature.
T.C.3 – Right Tower desiccant bed temperature.
2.
TEMPERATURE DISPLAY:
The temperature
measured at each thermocouple can be displayed,
one at a time, on the LCD screen of the remote I/O
module. Pressing the “TEMP DISPLAY” button on the
remote I/O module will display the temperature.
Each press of the “TEMP DISPLAY” button will
advance the thermocouple temperature displayed to
the next thermocouple in the above order. Pressing
the button a fourth time will display the current cycle
in minutes.
3.
TEMPERATURE UNITS:
The temperature measured
can be indicated in °C or °F. The unit can be
selected by changing the “UNITS” slide switch on
the back side of the remote I/O module.
4.
TEMPERATURE SETPOINTS:
For each location at
which a temperature is measured, there is a high
temperature setpoint. If the temperature for a given
area rises above its setpoint, the heater (LOAD 5)
will be disabled. The heater will be re-energized
when the temperature drops to the setpoint less the
specified hysteresis.
a. To set the high temperature setpoints move the
slide switch on the back of the module to the
“TEMP SET” position.
b. The high temperature set point to be adjusted will
be displayed on the LCD. Use the “TEMP
DISPLAY” button to choose which of the three
high temperature setpoints to change.
c. The high temperature setting will be displayed on
the LCD. Use the “UP” and “DOWN” push
buttons on the back of the remote I/O module to
set the temperature in 1°C increments.
d. The new high temperature setpoint will not take
effect until the selector switch is returned to
“RUN” mode.
5.
OPEN THERMOCOUPLE PROTECTION:
If an
open (disconnected or disabled) thermocouple is
detected, the heater will be disabled and a blinking
error message will appear on the LCD indicating
which thermocouple is open.
OPTIONAL CONTROLS AND ALARMS
1.
DEWPOINT DEMAND SEQUENCE CONTROL:
The dewpoint demand mode function will be
operational if there are 5 minutes before the end of
the drying cycle, and the dewpoint is below the
preset level. When in the dewpoint demand mode,
all of the timing functions stop. The yellow LED on the
remote I/O module will light up and “DEMAND
CYCLE” will be indicated on the LCD. When the
dewpoint reaches the preset dewpoint level, the
towers will switch and the normal mode cycle will
commence. The dewpoint demand mode function
will be disabled if the dewpoint is above the preset
level.
2.
HIGH HUMIDITY:
The high humidity alarm
function is indicated by a red LED on the remote I/O
module. The high humidity relay will energize for
remote annunciation. All the normal functions will be
maintained.
This unit may be damaged by electrostatic
discharge. Follow procedures for static
sensitive parts when handling, shipping or
installing this unit.
