Section 6: Meter operation

Reference, Installation, and Operations Manual

June 2013

3-9000-743 Rev S

 

 

Frequency data content

Each frequency pair is configured via the FreqXContent data point to represent actual (uncorrected) flow rate (0), standard (corrected) flow rate (1), average flow velocity (2), average sound velocity (3), energy rate (4), or mass rate (5).

Frequency data flow direction

The frequency pair output represents the data content (selected via FreqXContent) when the flow direction is in the selected direction (selected via FreqXDir). This option is available for all frequency content options except average sound velocity. The options are:

REVERSE (0): the selected data content is output when the flow is in the reverse direction.

FORWARD (1): the selected data content is output when the flow is in the forward direction.

ABSOLUTE (2): the selected data content is output regardless of the flow direction.

BI-DIRECTIONAL(3): the selected data content is output on channel “A” only when the flow is in the forward direction and on channel “B only when the flow is in the reverse direction.

Channel “B” operation on error

The frequency channel "B" can be configured to go to zero when the frequency data content is invalid by setting the IsFreqXBZeroedOnErr data point to TRUE (1). Setting this data point to FALSE (0) causes channel “B” to remain a copy of the “A” channel upon error. This option is available for all frequency data flow direction options except bi-directional.

Channel “B” phase

The Frequency Channel “B” phase relative to the channel “A” phase is selectable (via the FreqXBPhase data point) from the following options:

Table 6-11 FreqXB phase options
FreqXBPhaseFlowPhase Relationship

 

ValueDirection

 

 

 

 

 

 

 

 

 

0

forwardchannel “B”lagschannel “A” by 90 degrees
reverse

channel “B”

leads

channel “A” by 90 degrees

 

1

forward

channel “B”

leads

channel “A” by 90 degrees

reverse

channel “B”

lags

channel “A” by 90 degrees

 

This option is available for all frequency data flow direction options except bi-directional.

This selection only matters if the device to which the frequency outputs are connected are configured for Dual Pulse security and phase detection.

Maximum frequencyThe maximum frequency is selectable as either 1000 Hz or 5000 Hz (via the

FreqXMaxFrequency data point). The Mark III meter can overrange the selected maximum frequency up to 150% of the selected maximum frequency.

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Frequency outputs