Pure Humidifier INTAC, Инструкция по установке и руководство по обслуживанию

Страница: 10 / 32

8
MODES OF OPERATION DESCRIPTION
The INTAC
®
controller is preprogrammed at the factory for modulation control. The INTAC
®
will use the
analog input on plug J2 terminals 1 and 3 for voltage inputs and J2 terminals 2 and 3 for current inputs.
When programmed for “transmitter” mode on menu 502 a second modulating high
- limit input may also
be used on plug J4 terminals 5 and 7 for voltage inputs and J4 terminals 6 and 7 for current inputs.
ELECTRIC HUMIDIFIERS
SCR
The fastest acting mode of modulation available is SCR control. SCR stands for silicon - controlled
rectifier. Two SCRs are employed back - to - back in a device called a solid state relay (SSR). The SSRs
are used to switch the power on and off to each heating element on a very short time scale. The
INTAC
®
will send a pulse to each SSR according to the control signal for a percentage of the cycle time
of one second (field adjustable). For example at 50% power the SSR will be on for ½ a second and off
for ½ a second. This type of modulation is designed to provide extremely accurate control of the
humidifier output. For a three phase humidifier, each set of heating elements within the humidifier
evaporating chamber will be modulated to provide 0
- 100% modulating control of the humidifier output
(capacity).
GAS AND STEAM - TO - STEAM HUMIDIFIERS
STEAM
Steam mode is used when the INTAC
®
is used to control a steam - to - steam heat exchanger humidifier
type. Pressurized steam is introduced through a steam control valve into a heat exchanger submerged
in water. The valve modulation is controlled by an electric actuator. The INTAC
®
will control the electric
actuator with an analog control signal to modulate the amount of steam entering the heat exchanger
which will in turn control the amount of steam production on the outside of the heat exchanger. Up to 3
heat exchangers can be used in one humidifier. The control valves on multiple heat exchanger units are
typically set to run in parallel.
Steam mode can also be used for direct steam injection type humidifiers. The water tank related
controls are disabled when used for direct steam injection applications.
GAS
Gas mode is used when the INTAC
®
is used to control a natural gas or propane burner that is fired into
a heat exchanger submerged in water. The INTAC
®
will send a modulating analog signal to an actuator
that is mechanically linked to dampers that control the fuel and air entering the gas burner. The amount
of heat produced by the burner is modulated to control the amount of steam produced by the heat
exchanger. Up to 3 heat exchangers can be used in one humidifier. In a three heat exchanger
humidifier only the first burner modulates while the second and third burners are staged on and off.