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An
optional plug-in board provides an isolated 0-10 VDC signal for analog
closed-loop control, or to drive a chart recorder or remote display—plus
an isolated 0-20 mA or 4-20 mA signal for transmission to a computer or
central control room (thus turning any 2000 instrument into a
high-accuracy 4-wire transmitter, as shown in the figure below).
A
12-bit D/A converter provides 0.025% resolution. The update rate is
a fast 56/s at 60 Hz power (47/s at 50 Hz). The output selected in
software is calibrated to 99.9% accuracy, while the nonselected output is
accurate to 98%. Output for thermocouples, RTD's, and custom curves
is linearized to the displayed reading.
Isolation
to signal ground and power ground eliminates common ground-loop
problems. The isolation supply is powered by the basic meter, and
can drive 20 mA current into a load of up to 600 ohms with 12-V
compliance.
Both
voltage and current outputs may be easily scaled by front-panel push
buttons or by commands issued over the optional serial
interface. Both voltage and current outputs are available at the
same time, and the same scaling applies to both.
Depending
on the application, the analog output can track the filtered signal
input (for best noise rejection) or the unfiltered input (for
fastest response).
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0-20
mA output capability turns 2000 instruments into high-accuracy,
high-speed, isolated 4-20 mA TRANSMITTERS. The output is
linearized to the reading (a major benefit with thermocouple and RTD
inputs). The 4-20 mA signal can be transmitted via twisted
pair wires to a control room for supervisory process monitoring and
control. Model 2162 Process Signal Meters
in series with the signal can provide local readouts in engineering
units where required. |
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The
0-10 V output capability of the Analog Output Board is ideal for
driving a strip chart recorder. As with the 4-20 mA output,
the 0-10 V output can be scaled to the meter reading to highlight
signal-level changes in a range of interest.
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Analog
Output Specifications [Top
]
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Power
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Provided
by basic meter
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Signal
Source |
Filtered or
unfiltered digitized signal |
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Output
Linearization |
Linearized to
display |
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Output
Levels |
0-20 mA (or 4-20
mA) and 0-10 VDC |
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Compliance |
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0
to 20 mA |
12 V (0 to 600 Ω
load) |
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0
to 10 V |
2 mA (5 kΩ
min. load) |
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Accuracy
|
99.9%
selected output, 98% nonselected output
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Output
Nonlinearity
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Less
than 0.05%
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Output
Resolution
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12-bit
(0.025% of full scale)
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Output
Update Rate
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56/s
at 60 Hz; 47/s at 50 Hz
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Isolation
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Safety-rated
to 250 VAC, 4.2 kV peak per high-voltage test
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Response
Time |
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For
DPM |
17 milliseconds,
typical (unfiltered) |
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For
Counter Meter |
Gate time + 30 mx
+ 2 periods max. |
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Scaling |
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Reading
for Zero and Full-Scale Output |
-99,999 to +99,999
(DPM); -999,999 to +999,999 (Counter Meter) |
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Maximum
Span |
150 counts |
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