Panel Mounted Dissolved Oxygen Controller with a 2 x Control Relays and Isolated 4-20mA Output

The OD7635 Dissolved Oxygen Controller is available in either surface mounting or panel mounting configuration.

OD7635 Dissolved Oxygen Controller Introduction

The OD7635 Dissolved Oxygen Controller is a panel mounting Dissolved Oxygen controller with a large bright red LED digital display in a DIN spec. housing 96 x 96mm and is designed for the DN 47300 standard. This instrument also has a very short case length at only 95mm, allowing the controller to be mounted into compact sized control panels saving on both space and cost.

The easy to use OD7635 Dissolved Oxygen Controller has 8 buttons located on the front for easy access to the setup, configuration and calibration areas of the software. This allows the instrument to be easily setup and configured and makes periodic calibration a simple process with the dedicated Zero and Sensitivity calibration buttons.

To ease the installation of the OD7635 Dissolved Oxygen Controller the instrument is fitted with a switch mode power supply, suitable for a supply voltage of 86-264 VAC 50 / 60Hz.

The OD7635 Dissolved Oxygen Controller includes 2 x control relays for use in either High or Low operation and has a user configurable alarm relay which is operated when the Dissolved Oxygen reading is outside of parameter.

In addition, the OD7635 has a 4-20mA output isolated to 600Ω, making it ideal for incorporation into BMS or PLC systems, as well as with an online Data Logger or with a digital Chart Recorder.

The OD7635 is designed to work with either a Polarographic Dissolved Oxygen Sensor such as our model DES-1 or with a Galvanic Dissolved Oxygen Cell.

OD7635 Dissolved Oxygen Ranges

The OD7635 Dissolved Oxygen controller is able to measure both saturation and concentration of dissolved oxygen.  The ranges are as follows:-

OD7635 Dissolved Oxygen Controller Automatic Compensation

The OD7635 is a very sophisticated dissolved oxygen controller offering automatic compensation of the dissolved oxygen value against the following environmental influences:-

• Automatic Salinity Compensation
• Automatic Barometric Pressure Compensation
• Automatic Relative Humidity Compensation 
• Automatic Temperature Compensation

The Automatic Salinity compensation allows the instrument to adjust the concentration measurement (mg/L) according to the user input of the PPT of the chloride concentration of the sample. The automatic temperature compensation has a user selectable co-efficient with default setting 2.3% with a range between 0-4.00 % per °C.

Please contact us if you require any specific information about this element of the operation of the OD7635 dissolved oxygen controller.

OD7635 Dissolved Oxygen Controller with 4-20mA Output

The Od7635 has an industry standard 4-20mA output which correlates to the user selectable ranges. This ensures that the 4-20mA will give an accurate output corresponding to the range, with 4mA at the lowest point, and 20mA at the top of the selected range.

The 4-20mA output is isolated into 600Ω so that it is incredibly easy to connect to a PLC, Online Data Logger, digital Chart Recorder or other device.

OD7635 Dissolved Oxygen Controller with Control Relays

The front panel of the OD7635 includes 8 keys that allow simple navigation of the panel mounted dissolved oxygen controllers options.  The Zero and Span for the calibration procedure are mounted on to the front of the controller.  In addition both set-points are identified with their own front mounted button, allowing their values to be easily changed.

The dedicated Up / Down arrows on the front of the controller allow for easy modification of either the calibration or set-point values, decreasing initial setup time or the time spent during periodic calibration or maintenance.

The 2 x set-points control 2 x control relays which can be set to High or Low operation independently.  Each of the control relays include a variable hysteresis and a delay timer which can be set from 0-100 seconds.

In addition to the control relays, the OD7635 has a user configurable alarm relay which is energised when the dissolved oxygen value is outside the set parameters.  It has an easy set up feature and the operator has the ability to access the most frequently used functions.

There is also a logic input on the OD7635 which takes a volt free contact closure input.  When activated, the logic input isolates the output relays, preventing them from energising.  The Logic Input can be connected directly to the alarm relay if required.

OD7635 Easy to Operate Dissolved Oxygen Controller

The OD7635 is a simple to use Dissolved Oxygen controller.

In addition there is a password locked configuration screen which allows the user to change the less frequently adjusted settings.

For routine calibration of the instrument, the Zero and Span of the instrument are easily adjustable from the main menu, with a quick and easy menu driven calibration procedure.

The measuring range in mg/L or % is clearly visible on the front panel of the instrument, as is the current status of the set-point 1 relay, and the set-point 2 relay.  In addition the alarm relay status is clearly visible from the front of the instrument as is the logic input status.

The versatility of the microprocessor, accompanied with the user friendly software, allows the programming of the functions, routine checks and calibration to easily be accomplished, even by untrained operators.  Installation of the 7635 series of instruments is intended to be into a control panel or in the optional surface mounting enclosure.

The OD7685 Dissolved Oxygen Controller is an auto-ranging instrument ensuring the appropriate range is visible automatically even as the measure dissolved oxygen value changes.

OD7685 Auto-Clean Dissolved Oxygen Controller Introduction

The OD7685 Dissolved Oxygen controller is designed to offer accurate Dissolved Oxygen measurements in both environmental applications and in industrial processes such as boiler feed water and where the levels of dissolved oxygen are critical to process or industrial performance.

The OD7685 is a micro-processor based instrument and as such features accurate measurement of dissolved oxygen and a range of output options for the use with control equipment. 

With a wide range of control options, the OD7685 is a powerful dissolved oxygen controller. The 2 x control relays with On/Off functionality can be used to set to High or Low operation. There is a separate alarm relay which can be configured to energise when the dissolved oxygen value is outside of parameter. In addition there is a programmable industry standard 4-20mA output which is isolated into 600Ω.

Significantly the OD7685 includes an auto-clean relay for use with a compressed air system and suitable dissolved oxygen sensor, such as the Polarographic Membrane Cell DES-1 with autoclean nozzle. This allows the instrument reading, control relays, alarm relays, and 4-20mA output to be held while water or air are used to clean the membrane of the sensor, preventing residue which may blind or block the sensor from providing accurate readings.

The OD7685 operates from a power supply of either 115 VAC or 230 VAC 50/60Hz.

With a 16 character alphanumeric display, the OD7685 is able display the following ranges:-

OD7685 Dissolved Oxygen Controller with Automatic Compensation

The OD7685 dissolved oxygen controller is a very sophisticated instrument offering compensation for a number of external environmental factors including:-

• Automatic Temperature Compensation
• Automatic Thermo-resistance Compensation
• (Optional) Automatic Barometric Temperature Compensation
• (Optional) Automatic Relative Humidity Compensation
• Automatic Salinity Compensation (0 - 60'000 ppm)

The Automatic Salinity compensation allows the instrument to adjust the concentration measurement (mg/L) according to the user input of the PPT of chloride concentration of the sample. The automatic temperature compensation with a user selectable co-efficient (default setting 2.3%) between 0-4.00 % per °C.

In addition to using the conversion co-efficient's, the OD7685 includes a set of preprogrammed co-efficient tables within the micro-processor, to offer increased precision on automatically compensated values. Please contact us if you require any specific information about this element of the operation of the OD7685 dissolved oxygen controller.

OD7685 Dissolved Oxygen 4-20mA Output

The analogue output of the OD7685 can be configured to either 4-20mA or from 0-20mA as required. The output can be also be set proportionally or inverted to increase granularity or give proportional control to a compatible control device or aerator.

The 4-20mA can be scaled across 2 values within a range. So for instance, in the measuring range of the 0-200.0% saturation or concentration of 0-20.00 mg/L or ppm, the range could be 50-100% saturation or 10ppm-20ppm concentration.

The 4-20mA output is isolated to 600Ω and is designed to work with control equipment; PLC's; online Data Loggers, Chart Recorders or any other device that takes an industry standard 4-20mA signal.

OD7685 Dissolved Oxygen Controller Set-points and Relays

The OD7685 Dissolved Oxygen controller has 2 x Set-points which correspond to 2 x control relays offering On/Off control. These two control relays are 5 amp non-inductive and can be independently set from one another.

The control relays are also fitted with a user-selectable delay timer where the time can be set from 0-25 seconds as required. In addition the two control relays have an adjustable hysteresis value from ±10% of the set-point.

The OD7685 also includes an alarm relay which can be triggered to activate when the measured dissolved oxygen value is outside of parameter, with a delay timer of 1 minute. In addition, the alarm relay can be triggered following on from set-point 1 or set-point 2, with an adjustable delay from 0-60 mins activation.

OD7685 Auto-Clean Dissolved Oxygen Controller Summary

The OD7685 Dissolved Oxygen Controller is a powerful dissolved oxygen instrument offering a variety of accurate online dissolved oxygen measurements including percentage saturation, concentration and partial pressure.

With an isolated and programmable 4-20mA output, the OD7685 can easily integrate with control equipment and digital Chart Recorders easily. The control and alarm relays offer external control of aerators and other associated equipment to ensure that the dissolved oxygen can be accurately controlled or monitored for both environmental and process control applications.