Acromag DT335-0700, Руководство пользователя

Страница: 20 / 37

Model DT335-0700 Dual RTD/Resistance Input Transmitter w/USB
Acromag, Inc. Tel: 248-295-0880 - 20 -
http://www.acromag.com
- 20 - https://www.acromag.com
Configuration …
The Configuration screen for Dual Transmitter is the first
screen at left. When you click
the “ Configuration ” tab,
the software retrieves the unit’s current configuration.
The initial screen represents the
connected module’s
current configuration and operating mode before making
changes. Otherwise, you can load the configuration from
a saved file, or you may change fields as required. You
can always click
[Get I/O Config] to retrieve the
connected module’s current configuration at any time.
If you make any changes to the indicated configuration,
the only way to preserve the changes is to write them to
the device by clicking
[Send I/O Config] , or to save them
to a file by clicking “ F ile” in the upper left-hand corner of
the screen.
Select the Operating Mode...
The second screen at left shows the Operating Mode
selection. DT models have three modes of operation:
1
Dual Transmitter,
2
Single CH1 Transmitter, and
3
CH1
Signal Splitter. The Configuration Screen varies slightly
with the Operating Mode selected. To configure the unit
as a single CH2 transmitter (instead of CH1), select Dual
transmitter mode and ignore CH1.
Select the Input Type...
The third screen at left shows the Input Type selection.
•
If you select a RTD type, the output will be linear
with respect to the sensor temperature.
•
If you select Resistance , the output will be linear with
respect to the input resistance, not temperature, and
no special linearization will be performed.
Select the Input Range...
•
If RTD Input Type is selected, then the Input Range
menu will display RTD alpha values. Refer to “RT D
Resistance versus Temperature” section for an
explanation of alpha value.
•
If you select Resistance Input Type, the Input Range
menu will display resistance ranges. Select the lowest
resistance range that can support the input
resistance full-scale.
The ranges indicated are nominal and may be rescaled to
the output, such that you may use a portion of the input
range to drive the transmitter current or voltage output.
Because rescaling smaller will proportionally decrease
resolution, you should be careful to avoid going smaller
than 12-bits to achieve rated performance. Each halving
of the nominal range will reduce resolution by 1 bit.
Decreasing range resolution can magnify error, especially
noticeable for very small input ranges which degrade the
input signal-to-noise ratio and the resolution of the
analog-to-digital input conversion.