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GENERAL
The model OEM-1 is a system to control ozone generators and alarms based on an adjustable ozone concentration set-point. It is designed to work over a range of 0-0.1 ppm. Other versions of this product family will work over larger ranges.
One component of the OEM-1 system is the base board which incorporates the power supply, final signal processing, set-point controls, and the output relay. The other component is the sensor mounted with its associated electronics in a cylindrical DIN plug. This is precalibrated in our lab so that the sensor module and main board module together work as a calibrated system. If the sensor module is damaged, it is simply replaced by another precalibrated module. The sensor module can be plugged directly into the main board, or it can be separated by up to about 8 m (25 feet) by a DIN M/F extension cable.
The design incorporates hysteresis and time delay (set at 8 seconds except for special orders) to eliminate chatter and other excessive interactions between the sensor and generator. The SPDT relay contacts will handle up to 5 amps at 250 volts. The OEM-1 should not be used outdoors or in the presence of NOx, nitric acid, acid gases, or halogen Compound fumes
Allow warm-up according to the table below. At least 24 hours is recommended if the system hasn't been used for a week or so. This is because the sensor can absorb VOCs when it is not in use.
INSTALLATION
CAUTION!
The OEM-1 has exposed high voltage (110/220 V) solder points on the reverse side of the board from the large transformer. Do not connect high voltage AC power until you have arranged the board so as not to touch these points. It is best to bench test the board with a 12 VDC supply (see below) Do not let solder connections on the OEM-1 board short circuit to any metal surfaces.
The OEM-1 should be attached to your equipment (such as inside the ozone generator) by four mounting holes. Select four that align with your equipment and which stabilise the OEM board. The board surface on the solder side should be kept at least 6 mm (1/4") from any metal surface. The OEM-1 board should be wired to your power by the terminal block terminals 2 and 3 for 110 V 60 Hz or 220 V 50 Hz according to the power transformer wiring/jumper diagram found in these instructions. Alternately, you can power the unit by 12 V DC via jack J2. This low voltage power option was provided especially for bench testing the OEM-1 without exposing personnel to high line voltages. The Dryden Aqua P-20 AC adapter can be used to provide 12 VDC when 110 VAC 60 HZ is available. Otherwise, you will have to purchase this common size adapter locally with specifications according to our Tech Note P-101.
The complete terminal block wiring is;
Terminal
1. Circuit board ground. AC power connection - neutral. AC power connection - hot. Relay normally closed contact (N.C.). Relay common. Relay normally open contact (N.O.).
A typical ozone generator control would be for the hot wire to the primary of the generator high voltage transformer to be broken and connected through terminals 4 and S of the terminal block. This is the normally closed (N.C.) relay contacts. Terminals 5 and 6 are a normally open (N.O.) circuit and could be used, for example, to connect to remote alarm circuits.
To run AC power "hot" via the OEM-1 relay to the ozone generator high voltage transformer primary, solder a jumper to connect the two pads under the board that are connected to the terminal block's terminals 3 and 5.
If the sensor is not in a high ozone concentration, or hasn't warmed up, green LED D2 will illuminate, and will serve for start-up as a pilot light. The yellow LED C)1 illuminates when the relay is activated in response to high ozone. This will happen after a time delay programmed into the OS-1. 8 seconds is the factory setting if there are no purchase specifications to the contrary by the purchasing OEM. The delay happens both when the generator is turned on and when it is turned off. The time delay is determined by the value of C6, a tantalum capacitor. Removing that capacitor will eliminate the time delay. Time delays can be selected by multiplying a proposed Tantalum capacitor value by .75. For example, 4.7uF value for C6 would give about a 3.5 second delay.
WARM-UP When the generator or other equipment is turned off, if possible, it is best to wire the units so that the OEM-1 board is always powered. The sensor will stay heated and burn off any chemicals it would otherwise absorb. When the ozone generator or other equipment is turned back on, the OEM board is ready to respond immediately and accurately.
Otherwise, warm-ups are required. Recommended warm-up times are
Time Since Last Powered Warm-up Time 1 minute - 3 days 10 minutes 3 - 7 days 1 hour More than 1 week 24 hours If the sensor is easily accessible, the warm-up time can be minimised by checking for full response of the OEM-1 with the Dryden Aqua OG-2 Ozone Source Calibrator.
OPERATION
The OEM-1 is calibrated at the factory by comparison with a NIST traceable UV analyser. It is calibrated to-detect at .1 ppm. Lower detection points can be set by the calibrated dial pot R-14 on the main board. Its numbers represent percentage of ppm. For example, 50 on the dial pot is 50% of .1 or .05 ppm (50 ppb).The calibration as a percentage of .1 ppm should be within 20% over .03-.1 ppm. We do not recommend operating with a set-point for detection below .03 ppm because too many chemical, atmospheric, and electronic variables can collectively make lower set points inaccurate and unreliable. A rough check of the instrument's functionality and calibration in abusive environments should be done every three months. This can be done with our model OG-2 Ozone Source Calibrator (battery-operated pocket-size .1 ppm ozone generator).
CARE AND USE OF THE SENSOR
The sensor, which protrudes from the end of the sensor module, is a heated metal oxide (HMOS) sensor. It incorporates the latest IC and micro-machining technology in its construction so it is very stable and rugged. It can easily lose its calibration - at least until it is burned-in again - if it is exposed to any VOC chemicals and fumes; especially if it is exposed to these when it is not powered. These harmful fumes and chemicals include grease and oils, finger oil, strong deodorants, solvent fumes, sulphur compounds and the like. The sensor cannot be user calibrated. It should be recalibrated by an authorised distributor or by the factory. If it is damaged, a new sensor module must be purchased.
The sensor module can be plugged into the main board directly. It can be extended up to about 8 meters using standard DIN M/F extension cables (not mini-DIN) available from most computer supply distributors.
CALIBRATION
The sensor is calibrated in the sensor module by comparison with an NIST traceable UV analyser at .1 ppm. The accuracy is within 20% at .1 ppm.
AC ADAPTER
For using low voltage power input, such as for bench testing, an AC adapter that delivers 12 volts at 300 mA should be used. its output plug to fit our jack should have the 5.5 mm/2.5 mm female specification, jack centre pin +. These are widely available world-wide. For more complete specifications see our Tech Note P-101.
SPECIFICATIONS
Sensor: Heated metal oxide semiconductor. Range: 0-.1 ppm. Sensitivity: As low as .02 ppm. Accuracy: 20%. Response time: Within 1 0's of seconds. Turn-on, turn-off time delay: 8 seconds standard. Other times by request. Temperature and humidity range: Supply voltage required: 110 VAC or 220 VAC per OEM specification. Alternately, 12 VOC. Relay ratings: SPDT non-latching. Contacts: 5 amps at 250 volts AC or 1/8 HP inductive load. Size of main board: 83 X 83 mm (3.25" X 3.25"). Requires 23 mm (.875") clearance from top surface of board and 6 mm (.250") clearance from bottom surface of the board. Main board mounting: By 4 3.5 mm screws (or 6-32 screws). Sensor Module: 16 mm (dia) X 45 mm (length), (.62" X 1.75"), 10 9 (.3 oz) Shipping weight: Both modules and 2 meter sensor extension cable, no adapter: 454 g (1 lb)
PRECAUTIONS
• Read all instructions in this manual.
• Review safety procedures in testing and operating this system.
• Call a qualified electrician if you have any doubts about voltages, wiring, electrical codes and practices, etc.
• Keep the boards and sensor dry. Never let water or other liquids into the system.
Do not drop the boards. Damage may not be immediately obvious. Operate this system in areas of normal room temperature. Operation at lower temperatures, such as warehouses or refrigerated areas should only be attempted after testing in the proposed environment for correct and reliable operation. Do not attempt to service the instrument yourself. Do not operate this system or rely on its operations where there are high concentrations of:
• Chlorine or other halogen compounds
• Sulphur compounds.
• Nitrides of oxygen (NOx).
• Urine residues and ammonia compounds.
• Acid gases and vapours such as sulphuric or nitric acid fumes.
When in doubt, operate the system at least 24 hours in your worst case environment.
LIMITED WARRANTY
This product is warranted against defects in materials and workmanship for own year following the date of purchase by the OEM. This warranty does not include damage to the product as a result of misuse, damage, modifications or alterations, and it does not apply if the instructions in this manual are not followed.
If a defect develops during the warranty period, Dryden Aqua at its election will repair the product or replace it with new or reconditioned product of equivalent quality. In the event of replacement with a new or reconditioned product, the replacement will continue the warranty of the original model.
To return this system or any module of it, call your distributor or OEM. OEMs and distributors call Dryden Aqua at +44 18758 22222 or e-mail at: sales@drydenaqua.com to receive return instructions and a Return Goods Authorisation (RGA) number.
Except as provided herein, Dryden Aqua makes no warranties, express or implied, including warranties of merchantability and fitness for a particular purpose. Dryden Aqua shall not be liable for loss of use of this instrument or other incidental or consequential damages, expenses or economic loss, or claims for such damage or economic loss.
Installation Notes
1. line voltage is present on the board around terminal block TE31 Allow at least 0.25B inches (6.35 mm) clearance behind board. 2. All mounting holes are connected to circuit ground and also to position 1 of terminal block 3. Maximum component height above board mounting surface is 0.875 inch (22.25 mm) 4. Sensor plug is shown mounted directly to main circuit board, however extension cables may be used for remote mounting 5. Potentiometer R14 controls detector switching threshold. In standard configuration, 1B0X of scale equals 0.1 PPM. 6. till) D1 (yellow) is Illuminated when detected level is greater than threshold setting and relay is energised (after time delay). 7. LED D2 (green) Is illuminated when detected level is less than threshold setting. Responds quickly to Changes. 8. Connector J2 may be used to supply l)C power (12 Volts nominal, centre pin positive) to board for bench testing to reduce shock hazard. 9. Jumper pods on back of board may be used to select line voltages of 110 a or 220 VAc and to the relay contacts directly to line supply 10. Mounting holes are 0.125' / 3.175 mm diameter. Maximum outer Terminals stock Pinout
1. Ground (chassis).
2 Line neutral.
3 AC line hot
4. Relay normally closed contact.
5 Relay common.
6. Relay normally open contact.
Note: Board may be jumpered to connect relay common to AC line hot without external connection to terminal number 5. NC and NO contacts will thus provide switched AC for direct control of external devices.
