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Appendix E
log outputs on these channels are generated using DGH Corporation Model
3251 current output modules. These modules act as four wire transmitters,
i.e. power to the analog loop is provided by the DGH module. Each analog
output is electrically isolated from the remainder of the unit's circuitry.
Analog output channels are designated as Flow (QA+, QA-), Depth (DA+,
DA-), and Velocity (VA+, VA-). Connect each analog output channel to the
appropriate external loads/devices, consistent with standard current loop
wiring practices for 4-wire transmitters, and ensuring that the total load for
each loop does not exceed 600 ohms. NOTE: Although each of the three
available current loops has a distinct name, customized programming can
assign any function to any channel regardless of the naming convention on
the module's circuit board. Please consult any system-specific documenta-
tion or contact MGD Technologies, Inc. if you suspect your system may not
conform to the standard channel assignments.
E-2.7
Field Wiring/Pulse Outputs
Pulse outputs suitable for driving an external totalizer, sampler, or other
similar device are available with the appropriate microprocessor program-
ming. Pulse outputs are available as either +5vdc pulses (P5+, P5-) or as
dry contact closures (NO, Comm). The +5vdc pulse, if used, can source a
maximum current of 15 mA.
NOTE. Rev A: Dry contact closures are provided by a dry reed relay rated
for 200 million closures, with a maximum switching loads of 10 va, 100
volts, and/or 0.50 amps.
Rev B: Dry contact closures are provided by a solid state relay rated 3-60
vDC, 0.02 - 1.0 amps.
E-3
Setup and Calibrate the DGH Modules
The DGH Corporation modules (model D3251) used in the ADFM Analog
Output Module generate an isolated analog output signal based on ASCII
text commands received from the micro-controller. Software provided by
DGH can also be used to communicate directly with the modules for setup
and calibration purposes. Detailed information on the DGH modules is pro-
vided in the D3000/D4000 Users Manual. If you did not receive a copy of
this manual, please contact MGD Technologies Inc.
Standard DB-9 connector(s) are provided on the module's circuit board for
communicating with the DGH modules. These connectors are identified by
their nominal channel function, i.e. P2-Flow, P3-Depth, and P4-Vel. Con-
nectors may not be installed in unused analog output channels. Communi-
cation to the DGH modules can only be established when the module is dis-
connected from the unit's micro-controller. Setting dipswitches SW2-4, 5,
and 6 to the "Off" position accomplishes this.
page E-6
MGD Technologies, Inc.
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