TruDO Optical: Optical Dissolved Oxygen Sensor

TruDO Optical sensors are designed to provide comparable performance to electrochemical sensors, but do not use electrolytes, do not require polarization, and do not require frequent membrane replacement. The design ensures that the probe can remain in the bioreactor without maintenance during a sterilization process—which reduces damage or contamination risk.

No transmitter is required. The transmitter is already built into the sensor, thus saving the cost of a transmitter for every new installation. For existing installations, the sensor output signal can simulate a traditional DO sensor signal, thereby allowing TruDO Optical to be a plug-and-play replacement as well.

TruDO Optical Features

  • CIP, SIP autoclave compatible optical dissolved oxygen sensor
  • Equal or better performance than traditional DO sensors
  • Pressure and damage resistant membrane – up to 12 bar
  • Compatible with existing DO transmitters
  • 4 ppb to 300% saturation range

pH / DO Dual External Transmitter

1056 133X134

Dual External

The pH / DO dual external transmitter is a remote pipe or panel mounted instrument which is designed for the simultaneous measurement of pH and dissolved oxygen (DO) using sterilizable sensors. Finesse TrupH / TruDO sensors are plug-and-play with this transmitter. The transmitter prompts the user to configure each sensor loop in a few quick steps for immediate deployment. The transmitter also continuously monitors itself and the sensor for faults or errors, and provides easily recognizable alarm information to the control system or diagnostics on its screen. Its outputs are two 4 to 20 mA or 0 to 20 mA current signals that are electrically isolated and earthed (grounded). The external transmitter is the perfect solution for system retrofits.

Local Languages: The Finesse External Transmitter offers seven local languages: English, French, German, Italian, Spanish, Portuguese, and Chinese. Every unit includes user programmable menus, calibration routines, faults, and warnings; user help screens appear in all seven languages. The displayed language can be easily set or changed using the menus.


TruSens Transmitter

Trusens Transmitter 100X169

TruSens TX

TruSens blades (or digital transmitters) are mounted in a Finesse bioreactor controller and do not have a display or keypad. All blades provide automatic input of calibration data. The Virtual Transmitter module in Finesse TruBio® software allows full access to all of the blade’s functions, simulates a physical transmitter, and adds alarms and connectivity monitoring capability.




Sensor housing

TrupH and TruDO housings are designed to protect traditional 12mm pH and DO sensors when they are used in stainless steel bioreactors or fermentors. These housings are manufactured using 316L stainless steel and only use FDA approved wetted materials (e.g., o-rings). Finesse housings offer a standard PG 13.5 threaded insert for 12 mm sensors as well as a selection of interfaces with standard Ingold, B. Braun safety and sanitary ports.


Cable Connectors

D4cable 133X67

Custom cable lengths

TruCables™ are designed to securely connect sensors and transmitters and provide higher repeatability, increased signal stability and reduced noise in measurement signals. The cables are available with a variety of standard connectors and are also compatible with sensors made by other manufacturers. TruCables can be used in all bioprocess applications and vessel types.

DO Optical Sensors





Measurement Polarographic Polarographic Optical phase shift
Range 10 ppb to 200% sat 10 ppb to 200% sat 4 ppb to 300% sat
Temperature 0° to 135° C
32° to 275° F
0° to 135° C
32° to 275° F
0° to 130° C
32° to 266° F
Pressure 4 bar
58 psi max
4 bar
58 psi max
12 bar
174 psi max
Temperature Compensation 22 Kohm thermistor 22 Kohm thermistor 22 Kohm thermistor
Connector Type D4, VP6 D4, VP6 VP8
Sensor Length 120mm / 4.7 in 120mm / 4.7 in 120mm / 4.7 in
  225mm / 8.9 in 225mm / 8.9 in 225mm / 8.9 in
  325mm / 12.8 in 325mm / 12.8 in 325mm / 12.8 in
  425mm / 16.7 in 425mm / 16.7 in 425mm / 16.7 in
Cable Length  1,8 m / 6 ft 1,8 m / 6 ft 1,8 m / 6 ft
  6 m / 20 ft 6 m / 20 ft 6 m / 20 ft
Wetted Material 316L Stainless Steel 316L Stainless Steel 316L Stainless Steel
      USP Class VI silicone
Surface Finish Electro Polish RA12 Electro Polish RA12 Electro Polish RA12


Dual pH / DO Transmitter

Physical Description

Case Material Polycarbonate
Rating NEMA 4X/CSA (IP65)
Dimensions (H x W x D) Overall: 155 x 155 x 131 mm / 6.10 x 6.10 x 5.15 in Cutout: 1/2 DIN 139 x 139 mm / 5.45 x 5.45 in
Mounting Remote, panel or pipe mounted (kit included)
Conduit Openings Accepts 1/2 in or PG 13.5 conduit fittings
Display Monochromatic graphic LCD, 128 x 96 pixel display resolution Display area: 58 x 78 mm / 2.3 x 3 in
Weight / Shipping Weight 1.5 kg / 2kg (3 lbs / 4 lbs)
Power supply 20 to 30 VDC @ 15 W
Signal Outputs 2x Isolated analog 4 to 20mA
Output accuracy ±0.05 mA
RFI/EMI EN-50081/ EN-50082/ EN-61326
Operating Temperature 0° to 55° C / 32° to 131° F
Storage Temperature 0° to 60° C / 32° to 140° F
Relative Humidity 5% to 95% (non-condensing)



Wetted Materials 316L stainless steel
Sensor Connection PG 13.5
Port Connections Standard, safety and 1½ in sanitary
Pressure 6 bar / 87 psi
Insertion Guarded and unguarded

TruFluor DO

TruFluor™ DO sensors, designed for single-use applications, combine USP Class VI materials with a patented optical design to maximize reliability and optimize performance.