OxyGuard 1 Portable

The OxyGuard 1 system measures dissolved or gaseous oxygen.

Typical uses are:

  • Dissolved oxygen monitoring in sewage treatment plants.
  • Effluent monitoring in industry, land fill sites etc..
  • Monitoring of oxygen levels in clean water, beverages, oil etc..
  • The measurement of the purity of oxygen gas from oxygen generators.
  • Alarm monitor for the contamination of inert or other gas by oxygen.
  • Safety monitor where air could contain too low or too high oxygen levels.

OxyGuard 1 meets all of the usual demands made to such equipment, and has a galvanically isolated analogue output and three relay outputs with individual set points. The system is flexible; the user can change the range setting, choice of alarm function and analogue output type.

OxyGuard 1 comes complete with probe and accessories for several years normal use. The probe - the OxyGuard Standard Probe - is designed to last a lifetime with a minimum of maintenance!

Technical Advantages


  • 12 measurement ranges the user can easily change the range.
  • 0-20 or 4-20 mA analogue output, max. load 750 ohm.
  • Power supply either 230/115 VAC or 24 VDC.
  • Three relay outputs can be individually set to normally open or normally closed operation.
  • Wall-mount and panel-mount versions.
  • Full galvanic isolation between input and outputs.


  • Galvanic type - True zero. With built-in temperature compensation.
  • Excellent long-term stability.
  • No practical limit to cable length - extension can be made with any type of cable.
  • Needs only very small water flow for correct measurement.
  • Tough membrane can be wiped clean with cloth or paper.
  • Does not need regular service or renovation.
  • Wide range of armatures and fixtures - e.g. the Pioneer for use in sewage treatment plants, the Air Alarm for worker safety in areas where fluctuating oxygen levels could occur, Flow Cell etc. Ask for details.
  • Wide range of accessories - e.g. the EasyCal calibrator, OxyClean compressed air cleaner etc.



Dimensions: Diameter = 58 mm, length = 59 mm. Standard cable length = 5 m.
Weight: 400 g incl. cable.
Principle of Measurement: Galvanic cell, self polarizing, self temperature compensating.
Operating Conditions: 0 to 40°C, and pressure to 10 atm. or more (liquid measurements only).


Construction: ABS/Acrylic enclosure containing front panel with display, set point and calibration adjustments; main circuit board with power supply, terminals, electronics and relays.
Dimensions: 1W: b x h x d: 175 x 235 x 85 mm. 1P: Cut-out 66 x 137 mm., depth 150 mm.
Weight: Approx. 1 kg
Supply: 230/115 VAC or 24 VAC. Please specify when ordering.
Operating Conditions: -10 to +50°C. Enclosure rated IP65.
Output: 0/4-20 mA. Max. load 750 ohm. Fully galvanically isolated from the input
Range: ppm: 0-5.0, 0-10.0, 0-20.0 and 0-100.0 ppm. (mg/l). % sat:, 0-50.0, 0-100, 0-200 and 0-1000 % sat, % volume: 0-25.0, 0-50.0 and 0-100% volume
Accuracy/Repeatability: Accuracy depends on method of calibration and reference method. Repeatability is typically better than +/- 0.5% of measured value.
Relay Outputs: 2 alarm output relays, marked "HI" and "LO", with potential free changeover contacts. The relays are normally energized for fail safe operation.
One CON output - potential free changeover contact.

Ordering Information

OxyGuard 1W: B011W OxyGuard 1P: B011P
OxyGuard 1W for ambient air monitoring (with AirAlarm): B011WR
OxyGuard 1W for gas purity (with gas flow cell): B011WG
Portable version of OxyGuard 1W: B011T
The equipment is delivered ready for use