Michell Instruments XZR200, User Manual

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XZR200 User’s Manual
2 97337 Issue 4, July 2018
INTRODUCTION
1.2 Description
The XZR200 is designed to determine the oxygen concentration in air or inert gas
mixtures within a temperature range of -100 to +250°C (-148 to +482°F). The high
temperature option increases the maximum allowable sample temperature to +400°C
(+752°F). The XZR200 is particularly suitable for measuring oxygen in areas that are not
easily accessible, or in closed systems such as ventilation pipes, fl ues and containers.
The XZR200 can be user-con fi gured to output measuring ranges of 0 to 25% O
2
or
0-100% O
2
. The entire measurement range is linear in both cases. Factory default is
0 to 25% O
2
. When con fi gured for 0 to 100% O
2
the user can also modify the analog
output ranges to suit their application. The oxygen concentrations are simultaneously
output via 2 output channels (4-20mA and 0 to 10 V DC or RS232 Rx and Tx) - both
channels are referenced to the system ground (GND).
The outputs can be con fi gured to either 4-20mA and 0 to 10 V DC or RS232 interface.
Prior to shipping, all XZR200's are precon fi gured with a measuring range of 0.1% to
25% volume O
2
with linear 4-20mA and 0 to 10 V DC outputs. All settings can be
changed by the customer, should the measurement or interface requirements change,
by simply altering the position of jumper links on the PCB. The electronics are housed
in an IP65 die-cast aluminum housing.
The oxygen sensor is mounted in the tip of the stainless steel probe and is protected
by a stainless-steel sintered cap which acts as both a large particulate fi lter and also as
a fl ame trap.
A digital 3.3 V DC logic output cycles at the same frequency as the electrochemical
pumping action of the oxygen sensor during normal operation. This provides a real time
sensor health check; if the output ceases to cycle the sensor has entered a start-up or
fault state. The digital output is also used during the calibration process to indicate the
interface status.
A green on-board LED mirrors the CYCLE output and can be used to visually determine
the sensor status or during the calibration process. The red LED indicates the unit has
power applied.
The sensor measures the partial pressure of oxygen within the measurement gas and not
the oxygen concentration. In order to output an oxygen concentration (%) the XZR200
must be calibrated (more speci fi cally re-referenced) in a known gas concentration,
typically normal air. Calibration data is stored on power loss.
The automatic or manual calibration function is user-con fi gurable. Regular calibration
removes the effects of application and atmospheric pressure changes and also eliminates
any sensor drift that may occur during the fi rst few hundred hours of operation.