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DewPro MMY245
4 Field Validator Operation
In addition to being a versatile moisture analyzer for spot-checking gaseous streams, the DewPro
MMY245 may also be used as a field validator for most versions of the permanently mounted DewPro
MMY3 series loop-powered transmitters. The following is a list of the model numbers that are supported
by the MMY 245:
MMY 3 (0, 1)(R, A, B, C)(1, 2)(A, B, C, D)(1, 2)(A, B, C) Version 1
MMY 3 (all) Version 2
The version number is not encoded in the model number or noted on the identification plate. Is identified
by the configuration of the terminal board inside the unit. Figure 6 shows the difference in the two versions.
Version 1 (no socket)
For model numbers not listed above, contact the factory for recalibration and certification.
The DewPro
series transmitter concept includes a method for validating units in the field using a standard
moisture sensor to compare measurements while the transmitter was in service. This feature has been
incorporated into the MMY 245 with the flexibility of performing either a single point calibration or a two-
point calibration while the transmitter remains in operation. The primary function is to verify whether a
permanently mounted transmitter is functioning properly, and in calibration and, if not, then apply the
correct data to the EEPROM to realign its reading. Although factory recalibration of the MMY 245
analyzer is recommended every 6-12 months depending on use as a spot check instrument, it should be
recalibrated within 4 months prior to MMY 3 series transmitter field validations.
When the MMY 245 is used to field-compensate a DewPro
remain in service throughout the procedure eliminating down time, recalibration and shipping costs.
Another intrinsic benefit of performing a validation in-situ is that the unit is verified to be correct at the
exact measuring range where it will normally operate. This is usually a more limited range than that of the
factory calibration and thus can actually reduce small cumulative errors over the narrower range.
The validation can be either a single point (recommended) or a 2-point compensation (low and high dew
point). For either method, the MMY 245 is connected to the same sample as that for the MMY 3 transmitter
and monitors the sample and the performance of the on-line transmitter. The reading(s) are compared and
the EEPROM data on board the transmitter is automatically reprogrammed to correct any error(s).
GE General Eastern
Installation and Operation Manual
Display
Connector
Socket
Version 2 (with socket)
Figure 6
MMY 3, the transmitter will most often
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Troubleshooting
