Honeywell DCP552 Mark II O2 sensor check model with CP compensation, Objective, Setting

Chapter 5. FUNCTIONS

■O2 sensor check (model with CP compensation)

●Objective

As the O2 sensor starts to deteriorate, its output impedance increases. This function checks sensor output impedance and turns on the O2 sensor error event when the impedance exceeds 130kΩ.

●Setting

•One of the values set for setup data C71 to C74 is set to 11 to assign the O2 sensor check to an external switch.

•One of the values set for event configuration data setting E01-tto E16-tis set to 142 to assign an O2 sensor error event.

●Operation

•Two methods are used to perform an O2 sensor check. In one method the external switch which has been assigned the O2 sensor check function goes from OFF to ON. This is called a constant check.

•The other method the external switch is turned on each 24-hour period. This is

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called an automatic check.

•The impedance is checked when PV1 is 800 °C or more and the O2 input is

1000mV or higher.

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•The O2 sensor error event goes

on when

sensor

impedance

exceeds 130k;Ω

otherwise it remains off.

•The constant check method is

shown below.

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•The automatic check method is shown below.

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