TruDO: Dissolved Oxygen Sensor

The TruDO® family of re-buildable dissolved oxygen sensors is designed to be a cost-effective solutions where each sensor can be renewed (membrane or electrode). TruDO sensors have been specifically designed to minize drift in bioprocess environments, survive frequent sterilization cycles, and ensure measurement consistency from batch to batch.

TruDO Benefits

  • Fast response time
  • Resistance to bubbles
  • Repeatable performance
  • Suitable for autoclave, SIP and CIP
  • Certified “Like for Like” replacement for
    Broadley-James / Mettler-Toledo (Ingold)

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 Sensors Specifications





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
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
Electro Polish


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 / 2 kg (2 kg / 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.