12
3.4 Proportional adaptor (option)
The proportional adaptor can be either factory fitted or fitted subsequently by the customer simply by inserting it onto
the electronics unit.
The following control signals from humidity controllers can be processed:
0-2 V
0-5 V
0-10 V
0-16 V
0-20 V (SCS) 1-5 V
2-10 V
0-20 mA
4-20 mA
potentiometer min. 135 Ohm
3.5 RS 485 interface
The standard RS 485 interface provides a data transmission system in accordance with the American EIA (Electronic
Industries’ Association) standard, permitting high-speed transmissions free of disturbance. Data are transmitted in series
via two wires. To supply the accessories with power, there is a 24 V d.c. system with two other wires.
The bus structure enables both closed and open lines with stub cables and branches (tree system).
Transmission is performed on a twisted and screened two-wire cable, at distances of up to 1.2 km without amplifiers,
and with up to 32 subscribers.
4. Putting into operation
4.1 How the humidifier works
NORDMANN humidifiers use ordinary tap water to
produce steam. The water is converted directly
into steam in a steam cylinder by electrode heating
using electrical energy. In so doing, the water
acts as the electrical resistance. Vaporisation occurs
at atmospheric pressure (non-pressurised).
The electronic control system, with its highly-integrated microcontroller, regulates the vaporisation process in
accordance with a new principle developed by NORDMANN which allows rapid output changes to be made.
The humidifier adapts itself fully automatically to the quality of the water used. Due to this ability to set the optimum
water concentration in the steam cylinder, the smallest of adjustments to the water level can effect a change
in the steam output. Therefore, the unit reacts quickly and accurately to any setpoint changes. Because of its ultimate
degree of efficiency, this new type of control system ensures perfect drainage, i.e. the process of water decon-
centration in the cylinder. The use of fuzzy logic technology improves the controllability. The microcontroller of the
AT 3000 series works with fuzzy-logic algorithms. This regulates the conductivity or mineral concentration in the
steam cylinder and achieves ideal operating conditions while, at the same time, maximising the operational reliability.
Furthermore, the output fluctuations which occur during normal operation are kept to a manageable minimum
by the automatic water-intake and drainage functions.
S
E
E
Fig. 32
Hydrodynamic
filling cup
S = maximum-level sensor
E = electrode
