Electro-Tech systems 5112 User manual

DEHUMIDIFIER CONTROLLER
MODEL 5112
Operating Instructions
11/28/05

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1.0 INTRODUCTION
Many applications require the accurate measurement and control of relative humidity at a
defined set point below ambient for long-term applications in a seal environment. The Model
5112 Dehumidifier Controller is specifically designed to meet these requirements and can
be used to control dehumidification in virtually any type of sealed chamber. The controlled
115/230 VAC, 3 Amp output is able to control dehumidification systems that operate within
the limits of the controller's power handling capacity.
The Model 5112 is capable of is capable of measuring relative humidity over the entire 0 to
100% range. The standard sensor supplied with the Controller has a response time
satisfactory for maintaining long-term humidity stability. For applications requiring a fast
recovery time the optional ETS Model 554 Humidity Sensor should be used.
The Controller is designed to work in conjunction with ETS Desiccant/Pump
Dehumidification Systems (Models 5461, 5471 & 5478) and the Model 5465 Dry Gas
Dehumidification System (AC Solenoid valve controls the flow of dry gas). It may also be
used with other dehumidification systems that operate within the Model 5112 operating
parameters (2 Amps).
Any drying system can be used to control the humidity in virtually any sealed environment.
However, it should be noted that the larger the chamber, the greater the variation in relative
humidity throughout the chamber from the sensor reading. Good air circulation in the
chamber is critical to maintaining a uniform humidity level throughout the controlled
environment.
2.0 DESCRIPTION
The Model 5112 Dehumidifier Controller consists of two (2) basic components: a Humidity
Sensor and a Control Unit.
2.1 Humidity Sensor
The standard Humidity Sensor is an integrated unit measuring approximately
1”lx.438”wx.375”d that plugs into a 18” multi-conductor cable that is hard-wired to the
Control unit. Longer cable lengths are available as an option. A temperature
compensated capacitive sensing element where capacitance is proportional to
humidity is used to detect the relative humidity level. This type of sensor can
measure over the entire range of 0 to 100% R.H. with accuracy better than ±2% R.H
at a temperature of 20-40°C. The sensor has a slew rate (response time) of 0.35%
R.H./sec.
The sensor can be mounted to the wall of the chamber using an adhesive backed
clamp or Velcro or through a ½” NPT compression fitting inserted in the chamber
wall. Other mounting configurations can also be used to meet the user’s specific
requirement.

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2.2 Control unit
The Control unit provides the necessary indicators and controls to set the desired
humidity level and to measure the actual humidity level in the chamber.
The front panel of the Control unit contains a 0.375”, 3½-digit LCD readout for both
setting the desired set point and for reading the relative humidity with a resolution of
±0.1% R.H. A black momentary RH LEVEL, SET PT/READ switch selects the
information to be displayed. In the normal position the readout displays the measured
relative humidity level. In the depressed position, the readout displays the desired
humidity set point. When released, this switch automatically returns to the READ
position. A 10-turn screwdriver adjustable potentiometer is used to adjust the set
point from 0 to 100% R.H.
A separate pushbutton switch controls the Dehumidify function. When the
DEHUMIDIFIER switch is in the OFF position, the Model 5112 operates as a
precision electronic hygrometer.
The system Power switch and the controlled North American 3-prong grounded outlet
are located on the rear panel.
The Control unit is housed in a flame resistant Noryl,SE1 GFN1 housing that
conforms to the dimensional standard DIN 43700. The case measures
3.78”Wx3.78”Hx3.35”D (96x96x85mm). To install the control module into a panel a
3.62”x3.62” (92x92mm) cutout and the optional panel mount kit are required.
2.3 System Operation
Figure 2.3.1 is a block diagram illustrating the Dehumidifier Controller used with any
dehumidification system installed in an ETS 5500 Series Humidity Control Chamber.
Figure 2.3-1 Controlled humidity chamber block diagram
The Humidity Sensor measures the relative humidity inside the chamber. The Sensor
output signal is then compared to the set point. If the humidity measured in the
chamber exceeds the set point by more than 0.5% R.H. the Controller turns on the

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pump circulating the test chamber air through the desiccator or injecting dry gas
through a solenoid valve. For the desiccator system the desiccant absorbs moisture,
thereby lowering the humidity level inside the chamber. When the set point humidity
level is reached, the Controller turns off the pump. The pump will then cycle on and
off automatically as required by the Controller to maintain the desired humidity level.
Power to operate the Dehumidification System is controlled by a 3 amp solid-state
relay. When the measured humidity deviates from the R.H. set point the Controller
turns on the relay which then supplies the necessary 115/230 VAC power to the
system.
3.0 SYSTEM DESCRIPTION
3.1 Controller Front Panel
Figure 3.1-1 shows the indicators and controls located on the front panel of the
Control unit. The following is a description of each switch/indicator/display function.
Figure 3.1-1 Control Unit front panel
3.1.1 Indicators
3.1.1.1 % RH
This indicator is a 3½-digit LCD readout that is used to display both
the measured humidity and the desired humidity level set point.
3.1.1.2 DEHUMIDIFIER ON
This indicator is a Green point source LED that shows power to the
dehumidifier outlet has be turned on.

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3.1.2 Controls
3.1.2.1 READ RH/SET RH
This is the black momentary pushbutton switch. In the normal (out)
position, the measured humidity level is displayed on the LCD
meter. When depressed to the SET RH position, the humidity level
set point is displayed. Upon release, the switch returns to the READ
RH position.
3.1.2.2 RH SET ADJ
This control is a screwdriver adjustable, 10-turn potentiometer used
to select the desired humidity set point level. In the fully
counterclockwise position, the readout will indicate 0R.H. and in the
fully clockwise position the readout will indicate 100.% R.H.
3.1.2.3 DEHUMIDIFIER ON/OFF
This push on/push off switch, when in the ON position (in), places
the system in the DEHUMIDIFY mode. When the measured
humidity is above the set point level, a control signal activates the
DEHUMIDIFY relay circuit and 115/230 VAC is applied to the
DEHUMIDIFY AC outlet on the rear panel. This turns on the
Dehumidification System. When this switch is in the OFF position
(out) the Dehumidification System will remain off irrespective of the
RH level measured.
3.2 Controller Rear Panel
Figure 3.2-1 shows the rear panel. The following is a description of each component
function:
Figure 3.2-1 Control Unit rear panel

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3.2.1 POWER
The Power switch, Fuse and AC line cord are separate components that
control the power input to the Model 5112 Controller. The AC line cord is a
standard North American 3-prong grounded type, 8” (2.5m). The Model 5112
contains a universal power supply that operates from 90-260VAC, 50/60Hz.
Optional line cords are available to conform to the requirements of other
countries when ordered with the Controller. Otherwise, the user must use
either an adapter or cut off the plug and install the appropriate type.
The ON/OFF switch located on the rear panel, controls the ON/OFF status of
the Controller. The AC line fuse is located internally on the PC board and
protects both the controller electronics, and the solid-state relay. It is a 3AG
Slo Blo type rated at 250 Volts, 3 Amps. The solid-state relay is not voltage
dependent and is capable of switching a maximum of 3 Amps at either
voltage, however, for extra protection a 2 Amp fuse is installed.
NOTE:
A 115 VAC pump or solenoid must be used when operating at 115 VAC
and a 230 VAC pump or solenoid must be used when operating at 230
VAC.
3.2.2 DEHUMIDIFY AC Output
This fused, AC output receptacle accepts the standard 3-prong North
American grounded plug. When the measured humidity exceeds the humidity
level set point by about 0.5% R.H., 115/230 VAC power is applied to the
receptacle. The maximum current that this circuit can continuously supply is
fused at 2 Amps. However, under certain circumstances a 3 Amp fuse can be
used.
3.2.3 SENSOR IN
This 18” (46cm) hard wired cable provides the input/output interconnect
between the Controller and the Humidity Sensor. The sensor end is fitted with
a flat, 4-pin female receptacle with the following pin-out configuration:
Pin-1 Temp Signal In (0-5V)
Pin-2 Power (2-5.5VDC)
Pin-3 RH Out (0-5V)
Pin-4 Ground

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4.0 INSTALLATION AND OPERATION
4.1 Initial Check Out
Unpack the Control Unit and Sensor and inspect for visible damage. If no damage is
observed then proceed to check out the system as follows:
NOTE
All equipment being used with the Controller must match the voltage
selected.
1. The Humidity Sensor is already connected to the control unit when shipped.
2. Connect the line cord into the appropriate power outlet (MAINS). Be sure the
POWER switch is in the OFF position and the DEHUMIDIIFIER switch is in the
OFF (out) position. Plug the dehumidification system into the AC outlet.
NOTE
All ETS operating systems utilize the standard 3-prong North American
plug. A 230V/50Hz system will be marked as 230V, but will still have the
same 3-prong plug.
3. Turn on the Controller. The LCD readout should read some very low humidity
level and the Green DEHUMIDIFIER indicator should be OFF.
4. The LCD reading should slowly start to increase until it reaches the ambient RH
level. This may take as long as 5 minutes if the ambient humidity is very high.
6. Depress the READ RH/SET RH Switch to the SET PT position. The Display will
read some level. While holding the switch down in the SET PT position, rotate the
ADJUST Control to the desired RH level set point using a small (1/8”/3mm)
screwdriver.
7. Release the switch so that it returns to the READ RH (out) position and note the
humidity level reading on the display. Turn on the DEHUMIDIFIER switch (green
button out). If the set point is below ambient the green DEHUMIDIFIER ON light
will turn on and power will be applied to the Dehumidifier outlet, activating the
dehumidification system. If the SET PT is above the ambient RH reading the
Green LED indicator light will be off.
8. The dehumidification process will start. The dehumidification system will remain
on until the set point is reached.

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4.2 Installation
4.2.1 Sensor
The Humidity Sensor should be positioned in the test chamber to sense the
best average humidity condition within the chamber. The sensor is normally
installed using either the clamp or mounted in the bulkhead using the
compression fitting. Both items are supplied with the Controller along with a ½”
to 3/8” NPT reducer for installation in standard ETS Chambers.
CAUTION:
The sensing element is sealed within the sensor assembly, protected
against mechanical damage by a slotted housing cover. Under no
circumstances should the sensing element be touched. The sensor
should never be cleaned using compressed air. Dust and dirt particles
can be removed by blowing gently. There are no user serviceable parts
in the Model 5112 sensor.
4.2.2 Control Unit
The Control Unit may be placed on any surface near the test chamber or
installed into a panel (92x92mm cutout) using the optional mounting clips.
Plug the Dehumidifier into the AC Output receptacle. Plug the Controller line
cord into the appropriate power outlet (115 or 230 VAC). The Model 5112
Dehumidifier Controller is now ready for operation.
4.3 Operation
4.3.1 Initial Turn On
Turn on the Controller. (The POWER switch is located on the rear panel.)
Allow the Controller to warm up for approximately 5 minutes for the sensor to
stabilize.
4.3.2 Setting R.H. SET POINT LEVEL
Depress the black momentary READ/SET PT pushbutton and adjust the
ADJUST control for the desired R.H. set point as indicated on the LCD display.
A small (1/8”/3mm wide blade) screwdriver is required. When the correct
reading is obtained, release the switch. The display will then read the
measured humidity level.
4.3.3 Activating Dehumidify Function
If the desired humidity is lower than the ambient humidity measured, turn on
the DEHUMIDIFY function by depressing the green push-on-push off switch to

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the ON position. The Green DEHUMIDIFIER light will come on indicating that
the Dehumidification System has been activated.
As the humidity level in the test chamber begins to drop it will be detected by
the Humidity Sensor and displayed on the LCD meter. When the humidity level
in the chamber has been reduced below the set point, the Green LED light will
go out indicating the Dehumidification system has been turned off. As the
humidity level in the chamber gradually begins to increase above the set-point
level, the Dehumidification System will turn back on until the humidity level
drops back to slightly below the set point. The System will continue to cycle to
maintain the desired humidity within ±3% RH.
4.3.4 Using the Model 5112 as a Humidity Indicator Only
If the Model 5112 Controller is to be used as a humidity indicator only (no
humidity control), place the DEHUMIDIFIER switch to OFF. The system now
becomes a humidity level meter (hygrometer) only.
4.3.5 Dehumidification Systems
The Model 5112 Controller will control any dehumidification system that
operates within its power handling capability (2 Amps). The ETS Models 5461,
5471 & 578 Desiccant Dehumidification Systems and the ETS Model 5463 Dry
Gas Dehumidification System are described in detail in their appropriate
Operating Manuals.
4.3.6 Excessive Controller Cycling
Frequent on/off cycling of the dehumidifier may be indicative of a poor test
chamber seal or defective gloves. The chamber should be thoroughly
inspected to determine where the leak(s) are occurring and the problem
corrected.
5.0 CALIBRATION
The Model 5112 Controller is calibrated prior to leaving the factory. However, as with all
temperature and humidity measuring instruments, they must be calibrated periodically to
maintain specified performance levels. Calibration should be checked at least one or two
times a year depending on the operating conditions and the required measurement
accuracy.
NOTE:
If returned to the factory for recalibration or repair first obtain a RMA number from
ETS by calling 215-887-2196 Ext. 220.

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Calibration of the Model 5112 is performed as a complete unit.
Turn on the power and allow at least 5 minutes for the instrument to warm up. Place the
DEHUMIDIFY switch in the OFF position, then follow the procedure described below.
Calibration of the Controller requires either a known calibrated reference sensor for
comparison. As an alternative, certified calibration salt solution cells can also be used.
The Model 5112 is calibrated by comparing the relative humidity reading with the reading of
a known calibrated reference. The reference sensor should be placed next to the Model
5112 sensor and allowed to stabilize for at least 30 minutes before making any adjustments
to the sensor electronics.
Calibration can be performed either in the test chamber or in a separate calibration cell.
1. Remove the Sensor from its mounted position. If the Sensor is to be calibrated in
the chamber place the reference sensor next to it. If the Sensor is to be calibrated
outside the chamber, remove the Sensor from its installed position
2. Turn on the power. Allow at least 5 minutes for the system to warm up. The
Sensor and reference unit must be in a constant temperature environment of
73°F/23°C ±5°F/3°C and humidity environment for at least 30 minutes to obtain
humidity/temperature equilibrium prior to calibration.
3. Establish a required relative humidity level in the chamber such as 12%.
4. Read the temperature and relative humidity. Compare the reference unit reading
with the level displayed on the Dehumidifier Controller display. They should be
within ±2% R.H. of each other. If not, adjust the “1-point RH-calibration” control,
located through an access hole on the right-hand side of the control unit as shown
in Figure 5.1-2 until the correct reading is obtained. A small blade screwdriver is
required to perform this adjustment.
Figure 5.1-2 Calibration adjust potentiometer