Vaisala GMP251 Datasheet

GMP251 Carbon Dioxide Probe

For %-level measurements

Features

• Measurement range 0 … 20 %CO

• Intelligent, standalone probe with
analog and digital outputs

• Compatible with Indigo
transmitters and Insight PC
software

• Wide operating temperature
range (−40 … +60 °C)

• IP65-classified housing

• Integrated temperature

Vaisala CARBOCAP

measurement for CO
compensation purposes

• Compensations also for pressure,
oxygen, and humidity

• Sensor head heated to prevent
condensation

â

Carbon Dioxide Probe GMP251 is a new intelligent probe for

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measuring carbon dioxide. This robust, standalone measurement device is designed
for use in demanding applications, such as life science incubators, where stable,
reliable, and accurate performance is required.

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Benefits

• Superior long-term stability

• Reliable and accurate

• Calibration certificate included

GMP251 is based on Vaisala’s patented,
latest-generation CARBOCAP
technology that enables exceptional
stability. A new type of infrared (IR) light
source is used instead of the traditional
incandescent light bulb, which extends
the lifetime of GMP251.

GMP251 incorporates an internal
temperature sensor for compensation of
the CO2 measurement according to
ambient temperature. The eects of
pressure and background gas can also be
compensated for. The measurement
range is 0 ... 20 %CO2 and the sensor
performance is optimized at 5 %CO
measurement.

2

The operating temperature range of the
probe is wide (−40 … +60 °C
(−40 ... +140 °F)), and the probe housing
is classified as IP65. Condensation is
prevented as the internal sensor head is
heated. GMP251 is resistant to dust and
most chemicals, such as H2O2 and
alcohol-based cleaning agents.

Ease of use

GMP251 is a compact probe with easy
and fast plug-in, plug-out installation.
The surface of the probe is smooth,
which makes it easy to clean. The probe
provides several output options,
including analog current and voltage
outputs and digital RS-485 output with
Modbusâ protocol.

GMP251 can be connected to Indigo
series transmitters for an extended range
of output and configuration options. See

www.vaisala.com/indigo.

For easy-to-use access to field
calibration, device analytics, and
configuration functionality, the probe can
be connected to Vaisala Insight PC
software. See www.vaisala.com/insight.

Applications

GMP251 is ideal for life science
incubators, cold storages, fruit and
vegetable transportation, and for all
demanding applications where stable
and accurate %-level CO2 measurements
are needed.

A flow-through adapter with gas ports is
available as an accessory, enabling
tubing for easy and flexible remote
measurement with a separate pump. A
multiplexer can also be added for
sampling gas from several locations.

1)

1) Third-party pump and multiplexer not provided by Vaisala.

Technical data

Filter

96 mm, Ø 25 mm

M12 male
connector

12 mm

75 mm

9 mm

Measurement performance

Measurement range 0 ... 20 %CO

1)

Accuracy

At 5 %CO

2

At 0 ... 8 %CO

At 8 ... 20 %CO

2

2

±0.1 %CO

±0.2 %CO

±0.4 %CO

Calibration uncertainty

At 5 %CO

At 20 %CO

2

2

±0.07 %CO

±0.27 %CO

Long-term stability

At 0 ... 8 %CO

At 8 ... 12 %CO

at 12 ... 20 %CO

2

2

2

±0.3 %CO2/year

±0.5 %CO2/year

±1.0 %CO2/year

Temperature dependence

With compensation at 5 %CO2,

< ±0.05 %CO

0 ... +50 °C (+32 ... +122 °F)

With compensation,

±0.045 % of reading/°C

0 … 20 %CO2,−40 … +60 °C
(−40 ... +140 °F)

without temperature compensation at

-0.25 % of reading/°C

5 %CO2 (typical)

Pressure dependence

With compensation at 5 %CO
700 ... 1100 hPa

2

With compensation, 0 … 20 %CO
500 ... 1200 hPa

±0.05 %CO

±0.015 % of reading/hPa

2

Without compensation (typical) +0.15 % of reading/hPa

Humidity dependence

With compensation, 0 … 20 %CO2,

±0.7 % of reading (at +25 °C (+77 °F))

0 … 100 %RH

Without compensation (typical) +0.05 % of reading / %RH

O2 dependence

With compensation, 0 … 20 %CO2,
0 ... 90 %O

2

±0.6 % of reading (at +25 °C (+77 °F))

Without compensation (typical) -0.08 % of reading / %O

Start-up, warm-up,

and response time

Start-up time at +25 °C (+77 °F) < 10 s

Warm-up time for full spec. < 4 min

Response time (T90):

With standard filter < 1 min

Flow-through option with > 0.1 l/min < 1 min

With spray shield < 2 min

Flow rate dependence (for flow-through option)

Flow rate dependence:

< 1 l/min flow No

1 … 10 l/min flow < 0.6 % of reading/ l/min

1) At 25 °C (77 °F) and 1013 hPa (incl. repeatability and non-linearity).

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2

2

2

2

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eect

Compliance

Compliance marks CE, RCM, WEEE

EMC compatibility IEC / EN / BS EN 61326‑1, basic

elec

tromagnetic environment

Operating environment

Operating temperature of CO
measur

ement

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−40 ... +60 °C (−40 ... +140 °F)

Storage temperature −40 ... +70 °C (−40 ... +158 °F)

Humidity 0 ... 100 %RH, non-condensing

Condensation prevention Sensor head heating, when power on

Chemical tolerance (temporary
exposure during cleaning)

• H2O2 (2000 ppm, non­condensing)

• Alcohol-based cleaning agents (for
example ethanol and IPA)

• Acetone

• Acetic acid

Pressure

Compensated 500 ... 1100 hPa

Operating < 1.5 bar

Gas flow (for flow-through option)

Operating range < 10 l/min

Recommended range 0.1 … 0.8 l/min

1) Occasional short-term exposure to up to +90 °C (+194 °F) allowed, provided that the probe is fully
ins

talled inside the measured condition and power is switched on. Accuracy specification not

applicable if used in temperatures above +60 °C (+140 °F).

Mechanical specifica

tions

Weight, probe 45 g (1.59 oz)

Materials

Probe housing PBT polymer

Filter PTFE membrane, PBT polymer grid

Connector Nickel plated brass, M12 / 5-pin

IP rating, probe body IP65

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Connector M12 5-pin male

Dimensions

Probe diameter 25 mm (0.98 in)

Probe length 96 mm (3.78 in)

GMP251 dimensions

1)