ETS 5311 User manual

ETS 5311 User manual
MODEL 5311
Operating Instructions
Many applications require the accurate control of relative humidity at a specific point below
ambient for long-term applications in storage cabinets or test chambers. The Model 5311
Controlled Dry Gas System is specifically designed to meet these requirements. The
controlled solenoid activated valve regulates the amount of dry gas required to both
maintain a dry environment and conserve the amount of dry gas used in most sealed
The Model 5311 is completely self-contained and comes complete with controlled solenoid
valve, adjustable flow control valve, universal input voltage 12 VDC power module (90-260
VAC, 50/60 Hz), 5% RH sensor with ½” NPT compression fitting plus a ¼” NPT and a quick
disconnect fitting for ¼” polyflo tubing.
The standard sensor supplied with the Dry Gas System has a fixed set point of 5%. Sensors
with other humidity set points are available as an option. The Model 5311 is capable of
maintaining the humidity level to better than ±3% of the fixed controller set point with a
measurement accuracy of ±2% R.H.
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.
The Model 5311 Controlled Dry Gas System consists of two (2) basic components: a
Humidity Sensor and a Controlled solenoid valve with adjustable flow regulator.
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 module. 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 sensor is programmed at
the factory to produce a digital output about a pre-selected set point. The standard
factory setting is 5% RH where the sensor produces a 5V signal (ON) when the RH
level is >6% and a 0V (OFF) signal when the RH level is <3%. Other fixed RH set
points are available as an option. Contact ETS to order.
The sensor can be mounted to the wall of the chamber using an adhesive backed
clamp or Velcro or in the supplied ½” NPT compression fitting, shown in Figure 2.1-1,
that is mounted in the chamber wall. Other mounting configurations can also be used
to meet the user’s specific requirement.
Figure 2.1-1 Sensor mounted in compression fitting
A 18” (1m) hard wired cable provides the input/output interconnect between the
Control unit and the Humidity Sensor. The sensor end is fitted with a flat, 4-pin
female receptacle with the following pin-out configuration:
Temp Signal In (not used)
Power (2-5.5VDC)
RH Out (0-off/5V-on)
Control/Solenoid/Flow Regulator unit
The Control/Solenoid/Flow Regulator unit is shown in Figure 2.2-1. It will be referred
to as just the Control Unit.
Figure 2.2-1 Control/Solenoid/Flow Regulator unit
The Control unit is designed as a complete assembly. There are no user controls
except the flow regulator adjust knob. The only indicator is a Green LED that
indicates the solenoid is on and supplying gas to the chamber.
2.3 System Operation
Figure 2.3.1 is a block diagram illustrating the operation and installation of the Model
5311 installed in a sealed Chamber.
Figure 2.3-1 Controlled humidity chamber block diagram
The Humidity Sensor measures the relative humidity inside the chamber. If the
humidity measured in the chamber exceeds the fixed set point by more than 1% R.H.
the solenoid valve is powered and dry gas is injected. When the humidity inside the
chamber drops to 3% RH the solenoid valve is deactivated, shutting off the flow of
dry gas. The valve will then cycle on and off automatically as required by the
Controller to maintain the specified humidity level.
A 12V DC universal power module is used to power the Model 5311. It operates from
90-260 VAC, 50/60 Hz. For international applications the user will have to provide the
appropriate adapter plug to convert the standard North American 2-prong plug to
mate with the available power (MAINS) outlet.
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:
1. The Humidity Sensor is prewired to the control unit when shipped.
2. Plug the low voltage connector from the power module into the power jack located
on the bottom of the Control unit. Then plug the power module into the
outlet (MAINS). This will automatically power up the
Control unit. There is no power ON/OFF switch.
3. Wait a minute or two and observe the Green LED mounted on top of the unit. If
the ambient humidity is above the fixed set point the solenoid will be activated and
the LED should light.
3.2.1 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 supplied clamp or mounted in the ½” NPT
compression fitting supplied with the Controller. A ¾” to ½” reducer is provided
so the compression fitting can be mounted in standard ETS chambers that
come standard with a ¾” NPT fitting. A 0.875” (21mm) clearance hole is
required. Wall thickness must be less than ¼” (6mm).
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 5311 sensor.
3.2.2 Control Unit
The Control Unit may either be installed directly onto the chamber wall using
the fitted 2” (5cm) long, ¼” NPT threaded tube or the quick disconnect fitting
screwed onto the threaded tube so it can be placed at a remote location, using
¼” polyflo tubing to connect the solenoid gas outlet to the chamber using the
extra quick disconnect fitting. A small relief hole is required to prevent
pressure build-up in the chamber. The extra quick disconnect can be used for
this application.
3.2.3 Dry gas requirements
Typical dry gases are nitrogen, CO2 and dry air. Usually these gases are
under high pressure at the source. An appropriate pressure reducer should be
installed between the source and the Dry Gas Control System.
Gas flow to the chamber is controlled by the flow regulator connected to the
solenoid valve gas input. It should be adjusted for a flow rate between 10 and
50 cfm. If the chamber door is to be opened frequently then a higher flow rate
will reduce the humidity quicker. If the door is to be opened occasionally then
a lower flow rate will better conserve the dry gas. If the flow rate is to be
monitored then a flow gage can be installed between the valve output and the
chamber inlet. Ultimately, it is up to the user to determine the optimum flow
rate for the particular application.
The Model 5311 Dry Gas Control System is self-sustaining and does not need any
operator function to maintain the required humidity level. Once the unit is operating
and the proper flow rate established no further user action is required.
Frequent on/off cycling of the solenoid valve may be indicative of a poor chamber
seal. The chamber should be thoroughly inspected to determine where the leak(s)
are occurring and the problem corrected.
The Model 5311 Controller is calibrated prior to leaving the factory. There are no user
adjustable controls. Calibration can be checked by placing a calibrated humidity indicator in
the chamber next to the sensor and observe that the Controller is maintaining the humidity
within the specified range. If significantly out of tolerance or just does not work then the unit
will have to be returned to the factory for service.
If returned to the factory for repair, first obtain a RMA number from ETS by calling
215-887-2196 Ext. 220.
The Model 5311 should provide trouble-free service. If a problem with the system is
suspected, it is recommended the fault be initially isolated to either the Sensor, Control unit
or solenoid.
The following troubleshooting guide should assist the user in locating the more obvious
1. No Power - Check power at the wall outlet.
2. Green LED does not come on even though the humidity level inside the chamber
is known to be at least several percent above the fixed set point of the Model
5311. Return unit to factory.
3. Obviously incorrect humidity control – If sensor was removed from its connector,
check to see that it has been replaced properly. The arrow (5) should line up with
the left hand side of the sensor with the sensing grill facing up. If it was reversed
reinstall properly. The sensor will not be damaged if plugged in backwards.
Next, if the ambient humidity is near the fixed set point check sensor operation by
blowing gently onto sensor for several seconds and observe the Green LED. If the
LED turns on the humidity sensor and control electronics are at least working.
4. No dry gas flow, Green LED remains on constantly – Check to see if there is dry
gas at the source. If so then the valve may be contaminated preventing it from
opening or closing. Return the unit to the factory for replacement.
5. Difficulty maintaining low humidity within the chamber – The chamber may either
be leaking, ambient humidity may be very high or the flow rate is too low.
Generally, with a dry gas system the humidity within the chamber should recover
and stabilize within a few minutes. If this is not happening then try increasing the
flow rate. Also, check to ensure that dry gas is being injected. If dry air is being
used there may be condensation in the line.
Electro-Tech Systems, Inc. warrants its equipment, accessories and parts of its
manufacture to be and remain free from defects in material and workmanship for a period of
one (1) year from date of invoice and will, at the discretion of Seller, either replace or repair
without charge, F.O.B. Glenside, similar equipment or a similar part to replace any
equipment or part of its manufacture which, within the above stated time, is proved to have
been defective at the time it was sold. All equipment claimed defective must be returned
properly identified to the Seller (or presented to one of its agents for inspection). This
warranty only applies to equipment operated in accordance with Seller's operating
Seller's warranty with respect to those parts of the equipment which are purchased from
other manufacturers shall be subject only to that manufacturer's warranty.
The Seller's liability hereunder is expressly limited to repairing or replacing any parts of the
equipment manufactured by the manufacturer and found to have been defective. The Seller
shall not be liable for damage resulting or claimed to result from any cause whatsoever.
This warranty becomes null and void should the equipment, or any part thereof, be abused
or modified by the customer of if used in any application other than that for which it was
intended. This warranty to replace or repair is the only warranty, either expressed or implied
or provided by law, and is in lieu of all other warranties and the Seller denies any other
promise, guarantee, or warranty with respect to the equipment or accessories and, in
particular, as to its or their suitability for the purposes of the buyer or its or their performance,
either quantitatively or qualitatively or as to the products which it may produce and the buyer
is expected to expressly waive rights to any warranty other than that stated herein.
ETS must be notified before any equipment is returned for repair. ETS will issue an RMA
(Return Material Authorization) number for return of equipment.
Equipment should be shipped prepaid and insured in the original packaging. If the original
packaging is not available, the equipment must be packed in a sufficiently large box (or
boxes if applicable) of double wall construction with substantial packing around all sides.
The RMA number, description of the problem along with the contact name and telephone
number must be included in formal paperwork and enclosed with the instrument. Round trip
freight and related charges are the owner’s responsibility.
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