Fluke 2640A, 2645A user manual Analog Channels, Computed Channels, Channel Numbering, Mx+B Scaling

Overview 1

Instrument Features and Capabilities

Analog Channels 1-3.

The analog channel (1 to 20) measurement connections are made via the Universal Input Module. External signal conditioning for the analog inputs is not necessary. The host computer configures all analog channels using NetDAQ Logger.

Computed Channels 1-4.

In addition to the 20 analog channels, the instrument provides an additional 10 computed channels (21 to 30) by processing analog channels and other computed channels. The following methods are used:

∙The average of a group of channels,

∙The difference between any two channels,

∙The difference between a channel and the average of a group of channels,

∙A mathematical equation.

Channel Numbering 1-5.

Each instrument channel, measured or computed, is identified by Global Channel Number (GCN). The first two digits of the GCN are the Base Channel Number (01 to 99) that identifies the instrument. The last two digits are the channel number. For example, GCN 2618 indicates instrument 26 and analog channel 18 (below). When the instrument is in the quiescent state, the channel number of the GCN shows dashes, for example, 45-- for instrument 45.

SCAN

MON Mx+B ALARM

CH

Mx+B Scaling 1-6.

Mx+B scaling multiplies a measurement by a multiplier M and then offsets it by an offset B. For example, Mx+B scaling of 100x+50 applied to a measured or computed channel value of 1.15 results in a reading of 100(1.15)+50=165. A common use of Mx+B scaling is to calibrate a sensor or transducer to provide for display and recording in engineering units. The Mx+B annunciator lights when a monitored channel has scaling applied.

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