Pewatron FCX-ML-CH Series User manual

103-12-306-003-EH-0412.pdf
Manual
Oxygen module
FCX-MLxx-CH

103-12-306-003-EH-0412.pdf
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The items mentioned in this manual are trademarks and might be used for identification purpose.
Output protocol
Issue Month / Year Valid for Software version
1.1 February 2012
All rights reserved
This document may be used by the receiver for its designated purposes. It mustn’t be copied or
translated in any way without special consent in advance.
Technical amendments reserved.
Copyright: Pewatron AG
PEWATRON AG
Thurgauerstrasse 66
8052 Zurich
Switzerland
Tel: [phone]
Fax: [phone]
[email protected]
www.pewatron.com
Idt.-Nr.
Issue 1.1
Release 2.2012
Sold in North America by:
Servoflo Corporation
75 Allen Street Lexington, MA 02421
Tel: [phone]
www.servoflo.com / [email protected]

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1 List of Contents
Page
1. List of Contents ...............................................................................................................................................................................2
2. Customer Service...........................................................................................................................................................................3
3. Security Information ...................................................................................................................................................................4
4. Measuring Principle...................................................................................................................................................................... 5
5. Operation Start
................................................................................................................................................................................6
5.1 Mechanical Installation
............................................................................................................................................................. 6
5.2 Pneumatic Connections..............................................................................................................................................................
6
5.3 Electrical Connections
...............................................................................................................................................................7
5.3.1 Supply
.....................................................................................................................................................................................................
7
5.3.2 Analog Output
.................................................................................................................................................................................. 7
6. Environment Conditions
...........................................................................................................................................................7
7. Warm Up Time ................................................................................................................................................................................ 7
8. Gas Flow
.............................................................................................................................................................................................. 8
9. Calibration
…....................................................................................................................................................................................... 8
9.1 Calibration Adjustment............................................................................................................................................................... 8
9.2 Calibration Span and Zero...................................................................................................................................................... 8
9.3 Calibration if the sensor needs to replacing..............................................................................................................9
10 Important Advice
.........................................................................................................................................................................10
10.1 Restrictions
......................................................................................................................................................................................10
11. Specifications
.................................................................................................................................................................................10

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2 Customer Service
We at PEWATRON AG would like to offer the best possible customer service. Should you have any
questions, problems or comments regarding your FCX-MLxx-CH, we would appreciate if you get in
touch with us.
We recommend that all services, including repairs of the device, will only be taken care of by either our
customer service or by specially trained staff.
You can reach us the following address:
Headquarter:
PEWATRON AG
Thurgauerstrasse 66
8052 Zurich
Switzerland
Tel [phone]
Fax [phone]
E-Mail: [email protected]
Internet: www.pewatron.com
Before returning anything, please ask for an RMA-No.
Tel [phone]
Please send return goods to our Logistic Center:
PEWATRON AG
Logistic Center
Hardhofstrasse 31
8424 Embrach/ZH
Switzerland

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3 Security Information
Safety hazards that can endanger humans or do damage to the devices are specially mentioned in the
user manual.
Before installing the device you should read the instructions carefully. Please take note of all
paragraphs that point out possible hazards.
Warnings and instructions are expressed as followed:
!
Warning
Means that ignoring this instruction can endanger humans
Attention
Means that this instruction has to be followed in order to prevent damage to the device

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4 Measuring Principle
The sensor module is a complete solution for measuring oxygen within the range of 0,1...25%. The
sensor and the electronics are united on one board. The electronic amplifies the sensor signal and
puts it out as logarithmic current output signal 4…20mA ( according IEC 60381 )
Principle sketch of the O2Limiting-current sensor
The zirconia is pervious to oxygen ions when heated up to approx. 450°C. Therefore the oxygen gets
pumped out off a cavity by a current attached to the sensor. During a constant gas pressure the
amount of pumped-off oxygen equals the amount of the through the capillaries post-defunded oxygen
molecules and within a certain range independent of the current attached between the electrodes. The
measure current is proportional to the amount of the pumped-off oxygen molecules. The link between
oxygen partial pressure and sensor current is according to the following formula:
I
s= c In(1 - pO2 / pt)
means:
Is= sensor current
c = constant (sensor specific)
pO2= oxygen partial pressure
pt = gas pressure (total)
The sensor module takes care of two jobs:
- The link between oxygen partial pressure and sensor current
- Regulation of the heating performance of the sensor

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5 Operation Start
5.1 Mechanical Installation
The dimensions of the board are 75 x 40 x 28mm.
On every corner are mounting wholes with a diameter of 3,5 mm.
Attention
The board holds highly sensitive switches. While installing make sure that no
components get damaged mechanically
5.2 Pneumatical Connections
The flow housing has two pressure ports with 5mm diameter. The direction of the flow isn’t important.
Attention
Do never use silicone tubes.

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5.3 Electrical Connections
5.3.1 Supply
The module gets supplied with 7...28VDC through the clamps 1 (+) and 2 (-), approx. 200mA
(24VDC).
5.3.2 Analog Output
For the output signal the clamps 3 (+) and 4 (-) can be used.
6 Environment Condition
Also see item 11 in our specifications, especially for the temperature and humidity range (non-
condensing).
Not to be operated out doors.
Protect against humidity
The temperature of the sensor is 450°C. Be aware of possible dangers while handling sensitive gas
mixtures.
!
Warning
Potentially explosive Atmosphere
The device mustn’t be opened in a potentially explosive atmosphere.
7 Warm Up Time
The modules need a warm up time of approx. 3 minutes

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8 Gas Flow
Heed the following points:
-The flow should not be smaller than 0,1 and not larger than 3,0l/min. Optimal 0,5l/min
-We recommend to use a suitable filter, since the gas flow can contaminate the sensor,
which will shorten its life span considerably.
-Avoid condensation (H2O) inside the sensor housing.
9 Calibration
All necessary adjustments and calibrations are being done at the production site.
The output signal is to be read as followed:
4...20mA pO2(%) = 25 (lout [mA] - 4) / 16
means:
pO2: oxygen partial pressure in % of the total pressure
lout: output current in mA
9.1 Calibration Adjustments
It is recommended to check the device periodically by running it under regular lab conditions and flush
the sensor with regular air (20,95% O2).
9.2 Adjustment Span and Zero
The modules are calibrated and each module is supplied with a calibration sheet. The result of the
measuring at an environmental temperature of 25°C should be 20,95% O2±0,1% O2. Should there be
higher differences as expected try following procedure.

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1 Attach the module to the supply
2 Use the sensor in regular air (20,9% O2)
3 After 10min. adjust the output signal using the potentiometer 2. In a clean environment the
amplifier should have an output signal of 17,44mA (0,05mA).
4 Flow pure N2.
5 After approx. ca. 10min. adjust the output signal to 4,050mA 0,005mA using the potentiometer 1.
Achtung
The potentiometers on the boards mustn’t be tempered with.
This completes the calibration.
9.3 Adjustment if the sensor needs replacing
1. Attach the module to the supply
2. After approx. 10 minutes adjust the sensor heating (VH) at PIN 4 and 5 using the potentiometer 3.
Please note that the VH differs from sensor to sensor and has to be adjusted at an accuracy of
0,005V. The corresponding values can be found on the attached calibration sheet.
3. Use the sensor in regular air (20,9% O2)
4. After 10min. adjust the output signal using the potentiometer 2. In a clean environment the
amplifier should have an output signal of 17,44mA (0,05mA).
5. Flow pure N2.
6. After approx. ca. 10min. adjust the output signal to 4,050mA 0,005mA using the potentiometer
1.
This completes the calibration.