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ADFM Analog Output Module
E-1
Introduction
The ADFM Analog Output Module is an optional component of an ADFM
(Acoustic Doppler Flow Monitor) flow monitoring system. It enhances the
operation of a standard ADFM by providing a local data display and addi-
tional output options. The ADFM Analog Output Module is designed to
accept a serial RS-232 data stream from an ADFM, parse the data stream to
obtain depth, velocity, flow rate, and total flow information, display that
information on a local LCD display, generate analog output signals accord-
ing to user-defined scaling parameters (1 channel standard, 2
channels optional), and generate an output pulse at selected total flow in-
crements (optional). LCD data displays, analog output ranges, and total
flow pulse outputs are all provided in user-selectable engineering units.
Major components of the ADFM Analog Output Module include a pro-
grammable controller module, an LCD display panel, and one or more ana-
log signal generator modules housed in a NEMA 4X enclosure. The con-
troller module used is the Parallax BASIC Stamp IISX (BS2), based on the
Scenix SX micro-controller. As the name implies, the BS2 is programmed
using the Parallax PBASIC2 variant of the BASIC programming language.
Operation of the unit is controlled by the loaded BS2 program code, and in-
circuit reprogramming can be accomplished at any time.
Analog outputs from the ADFM Analog Output Module are generated using
DGH Corporation D3000 series analog output modules. These modules are
microprocessor controlled and programmed using ASCII commands and the
RS-232 communications protocol. DGH Model D3251 current output
modules are used, with the useable signal scaled from 4-20 mA and error
conditions signaled by outputs in the 0-4 mA range. Current outputs are
easily converted to voltage outputs using the appropriate precision resistor.
In operation, ASCII commands from the BS2 set the DGH module output
levels based on the data stream from the ADFM.
ADFM Technical Manual (January 2000)
ADFM Analog Output Module
E
Appendix
nd
rd
and 3
page E-1
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