ZBXYA025M0 Datasheet, PDF (3/5 Pages) Sensortechnics GmbH – Oxygen sensor interface boards

ZBXYA
Oxygen sensor interface boards
OUTLINE DRAWING & ELECTRICAL CONNECTION (cont.)
Operating and Calibration Notes for ZBXYA...D
Heater adjustment:
1. Check the sensor heater settings: Using a volt meter measure the voltage across H+ and H-. The heater voltage should be
4.35 ±0.1 V_DC. If using long cables (>1m) measure this voltage as close to the sensor as possible.
2. If the heater voltage needs to be altered then follow the next steps.
3. With the power off, remove the daughter board, and expose the heater voltage setting pot.
4. Apply power to the board.
5. Using a volt meter measure the heater voltage across H+ and H- and adjust the pot until the voltage is 4.35 ±0.1 V_DC.
6. Switch the power off and re-assemble the daughter board.
Auto-calibration of the sensor and board (only available for ZBXYA025D...):
Note: Auto-calibration assumes that the sensor is in a normal atmosphere (1013 mbar pressure, 20.95 % O₂ and typical
humidity levels giving an O₂ concentration of 20.7 %. The board adjusts its output to 20.7 %/25 % of full-scale.
1. Ensure the sensor is in ambient air (typically 20.7 % O₂). Remove or purge application environment.
2. Switch the power on and leave for 10 Minutes and allow to stabilise.
3. The green LED should be blinking, this indicates normal operation.
4. Voltage output devices: Measure the voltage at the K1 output and the 0 V (measuring circuit) terminal.
The reading should be approx. 8.28 V.
Current output devices: Measure the current at K1 output terminal through an external load resistor (typ. 200 Ω).
The reading should be approx. 17.25 mA.
5. If the reading is not correct then press and hold the calibration button for a minimum of 10 s until the reading is correct.
This may also be achieved using an external calibration switch (Normally Open) placed across GND (0 V Supply)
and K2 (see outline drawing).
6. Once released the green LED should start blinking again to indicate normal operation.
7. The system is now calibrated. (Please note that system calibration is lost on power loss and steps 1-8 must be repeated).
8. Note that the auto-calibration will only work if the output is within 20 % of the correct target value. If this is not the case,
the PCB will not attempt to calibrate and will indicate this by setting the green LED constantly on (until removal of power). If
this occurs it may be necessary to manually calibrate the system as described below.
Manual calibration of the sensor and board:
Manual calibration may be performed at any known O₂ content including normal air.
1. Ensure the sensor is in an atmosphere with known O₂ content (see table for calibration values).
2. Switch the power on and leave for 10 Minutes and allow to stabilise.
3. The green LED should be blinking, this indicates normal operation.
4. Voltage output devices: Measure the voltage at the K1 output and the 0 V (measuring circuit) terminal.
Current output devices: Measure the current at K1 output terminal through an external load resistor (typ. 200 Ω).
5. If the reading is not correct then adjust the calibration setting pot until the desired output is produced. Turn the pot clock-
wise to decrease the output value and counter-clock-wise to increase it. Because it takes some time for the output signal
to stabilise following an adjustment, make small calibration changes and allow to settle for 30 seconds each time. See
table for calibration values.
6. If the board is calibrated manually it will retain its calibration after the power is switched off.
O₂ concentration in normal
atmosphere (1013 mbar pressure)
20.7 %
90 %
25 %
5%
Board Test:
ZBXYA025...0
8.28 V_DC
-
10.0 V_DC
2.0 V_DC
Calibration values
ZBXYA100...0
ZBXYA025...4
2.07 V_DC
9.0 V
17.25 mA
-
-
20 mA
0.5 V_DC
7.2 mA
ZBXYA100...4
7.34 mA
18.4 mA
-
4.8 mA
1. The green LED should be blinking to indicate normal operation.
2. If the Test button is pressed a 20 % drop in the reading indicates normal operation.
May 2008 / 638
3/5
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