Spectrum Controls 1769sc-HART Modules User Manual
Page 60
Compact IO™ Isolated HART Analog Output Module
User’s Manual 0300217-03 Rev. A
6-8
Data Format
This selection allows the user to define the channel’s data format for any of the
following:
Raw/Proportional Data
The raw/proportional data format provides the best resolution of all the
supported data formats.
If you select the raw/proportional data format for a channel, the output
command word
1
will be a number between -32767 and +32767. For example, if
a 4 to 20 mA output type is selected, 4 mA corresponds to -32767 counts and 20
mA corresponds to +32767.
Engineering Units
When using this data format, the module scales the output command word
1
to
the actual engineering values for the selected output type. Values are expressed
with an assumed decimal place. Refer to Table 6-8 (Data Formats).
The resolution for the selected data format is dependent on the output type
selected.
Scaled-for-PID
The PID algorithm for the MicroLogix 1500 and other Allen-Bradley controllers
(i.e. SLC) utilize an engineering range of 0 to 16383. The scaled for PID format
allows the programmer to assign the output command word
1
for the selected
channel directly to the PID instruction’s CV variable, thus eliminating the need
for further scaling.
Percent Range
The output command word
1
for the selected channel is scaled using a range of 0
to +10000 counts. For example, if a 4 to 20 mA output type is selected, 4 mA
corresponds to 0 counts and 20 mA corresponds to +10000 counts.
Note: 10000 counts represent 100.00 percent.
Table 6-5 (Data Formats)
Output Type
Engineering
Scaled for PID Proportional Counts
Percent
0 – 20 mA
0 to 20000
0 to 16383
-32768 to 29646
0 to 10000
4 – 20 mA
4000 to 20000
0 to 16383
-29822 to 29085
0 to 10000
Reserved
Reserved for future expansion and should be set to zero.
6.3.14 Fault Value (Words 2, 10, 18, 26)
During a processor fault condition, the associated output channel will be driven to this
value.
Note: The range of this value is defined by the data format selected for the channel.
6.3.15 Program/Idle Value (Words 3, 11, 19, 27)
During a processor program or idle mode, the associated output channel will be driven to
this value.
1
Module output words 0 through 3 for channel 0 through 3, respectively.