Multiplexer Scanning

Use the Multiplexer Status dialog to:

  • perform the following offline configuration tasks:

    • enable and disable scanning by the multiplexer of HART field instruments

    • specify a Scan Mode

    • set maximum limits for both Communication Count and Busy Retry Count

  • monitor statistical data describing the operation of the HART multiplexer

  • diagnose the multiplexer status using status LEDs

HART Port Parameters

The following HART port parameters can be accessed in the Multiplexer Status dialog:

Parameter

Description

Scan Command

Specify a scan command:

  • Read PV

  • Read Current (mA) and % of Range

  • Read Current (mA), PV, SV, TV and QV

Scanning

Specify a scan mode:

  • ON: enable scan

  • OFF: disable scan

Communication Retry Count

Type in the number of times the HART interface module resends a command to a non-responsive HART instrument. Valid values = 0...5. Default = 0.

Busy Retry Count

Type in the number of times the HART module resends a command after receiving a busy reply from a HART instrument. Valid values = 0...5. Default = 0.

Gender

  • primary (default)

  • secondary

Search Algorithm

Type of search performed for instruments on the loop:

  • Poll Address 0 Only

  • Poll Address 0 to 15 (default)

  • Poll Address 0 to 63

Max Instruments Connected

The maximum number of instruments that can be connected to the multiplexer.

Instruments on Instrument List

The number of instruments on the instruments list.

Multiplexer Status

The Multiplexer Status dialog indicates the status of the multiplexer as a whole, and monitors the existence or absence of several multiplexer states. The status of each state is indicated by the LED color, as follows:

  • Red indicates the existence of a detected event of the specified type.

  • Green indicates normal operations.

  • Gray indicates the DTM is offline and is not communicating with the device.

The Multiplexer Status dialog displays the following multiplexer status states:

State

Description

Device Malfunction

A detected error rendered the instrument non-operational.

Configuration Changed

An operation occurred that changed the instrument configuration.

NOTE: Click Reset to clear detected faults and update module status.

Cold Start

The instrument was reset, or power was cycled off then on.

More Status Available

Additional instrument information is available via HART command 48 (Read Additional Status Information).