Software Features; Sample Conditioning Practices And Precautions; Internal Construction; Avoid Liquid Samples - GE DewPro MMY 245 Installation And Operation Manual

DewPro MMY245 Installation and Operation Manual
while the sensor itself is kept dry and ready to measure. Purging for 3-5 minutes is recommended. In
the "measure" position of the valve handle, the desiccant chamber is closed from any possible contact
with the incoming sample gas. This prevents the desiccant from being contaminated or consumed too
quickly. The desiccant should last several months under daily use for several readings per day.
An optional pressure transducer can be ordered to provide pressure information to the electronics for
compensation of readings in concentration units of measure. These units of measure require a total
pressure value to correctly compute the proper moisture reading. The pressure information can be
displayed and used for correction of the moisture reading from this pressure sensor or from a direct
input of a constant value as selected using the keypad.

1.3.3 Software Features

The software architecture is based on a matrix of operating parameters. Each parameter setting
determines the function of the software to display and compute the proper moisture value, to control
outputs and to communicate with field mounted MMY series transmitters. The matrix settings also
determine how to treat optional inputs and when they should be used in the computation of a moisture
value. The complete operation of the matrix is described in the Instrument Setup portion of the Basic
Operation, Section 2 in this manual.

1.3.4 Sample Conditioning Practices and Precautions

1.3.4.1 Internal Construction


All the wetted surfaces of the MMY 245 DewPro are electro-polished non-hygroscopic metal
components of either stainless steel or anodized aluminum. Introducing clean samples will prevent
these surfaces from becoming contaminated.

1.3.4.2 Avoid Liquid Samples

Avoid ANY liquid exposure of the sample lines and the instrument. Liquids will damage the unit and
void the Warranty.

1.3.4.3 Avoid High Temperatures

Avoid high or low temperatures. The MMY 245 can be operated over a temperature range of 4°F to
104°F (-20° C to +40° C). Operating the unit at higher temperatures can damage the sensor and the
electronics. The LCD is not likely to work if the unit is operated below the normal stated range.

1.3.4.4 Avoid High Pressure Samples

The maximum inlet pressure rating for the MMY 245 is 150 PSIG or 10 Bar. If the process or sample
pressure is greater than this, a pressure regulator should be used to drop the pressure to within the
instruments range.

1.3.4.5 Hazardous Gas Handling

When making connections to samples of flammable or hazardous gases, exercise care to insure leak
free connections. Be aware that leaks can create fire, explosive or toxic conditions that should be
avoided. The MMY 245 is designed to meet Class I, Division 1, Group B-G environments; but the
integrity of the sample connections to the instrument is the responsibility of the user.

1.3.4.6 Avoid Particulate Contamination

A sample contaminated with particulates will deposit some of this material inside the unit producing
more surface area and sites where moisture could be trapped. This could result in higher than actual
readings. If the sample contains particulates or aerosols, it must be filtered to remove this
contamination.
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