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11. Unit Control
11.1 General description
The standard controller can be used for both
electrode steam humidifiers and heater type
steam humidifiers.
Operation of the HygroMatik steam humidifier
is under microprocessor control.
For steam humidifiers with unit housing, a
control switch is located on the front panel of
the unit featuring two positions besides the
„Zero“-position for a switched-off device.
„Pos. I“ : The unit is switched on
„Pos. „II“ : Cylinder water is manually drained
For controlling the unit a control panel featur-
ing a 3-digit display and a number of icons
plus 4 touch keys is integrated in the unit
front panel. Controlling the unit by software
using the modbus RTU protocol is also possi-
ble. On request, modbus documentation is
available from your expert dealer.
For control signal processing inputs are avai-
lable whose properties may be defined by
parameter settings. Activating of the intake
solenoid valve, the blow-down pump and the
main contactor is achieved through relays on
the main PCB. Another relay serves for sig-
nalling purposes (factory setting is „collective
fault“).
As an ordering option, for provision of 2 addi-
tional switching functions, a pair of top-head
rail relays is available for the plugable con-
nection to the mainboard.
With heater type steam humidifier, the power
is controlled via a single-phase or two-phase
solid state relay (for devices with higher
power).
With electrode steam humidifier, the elec-
trode current is switched directly via one or
two main contactor(s) designed for the
respective device power.
Mainboard
The entire control logic, including the relays
for basic operation, is implemented on a
compact printed circuit board which, in the
case of steam humidifiers with device hous-
ings, is attached to the vertical partition wall
between the housing chambers.
All connections on the PCB are distinctive in
order to allow for easy exchange of the board
in case of maintenance.
On the main PCB, two vertically mounted
fuse holders with bayonet fitting encorporate
1.6 A fast-blow fine wire fuses (F1 and F2 for
L and N, s. section „Basis PCB connections“
in this chapter).
Safety systems
Besides the common external safety interlock
(implemented by means of a switching con-
tact or a through a building control system),
the following safety is encorporated in the
unit:
An electric heater type steam humidifier is
thermically controlled at two spots minimum.
Besides the thermo switch located on top of
the steam cylinder and meant for overheating
avoidance of the electrical heater element,
Control switch
Control pane
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