2 ANALOG INPUT MODULE REPLACEMENT
2 - 7
2.2.2 Function comparison
: With functions, -: Without functions
Item Description A616AD Q68ADV/I Precautions for replacement
A/D conversion enable/
disable
Specifies whether to enable or disable the A/D
conversion for each channel.
By disabling the conversion for the channels
that are not used, the sampling time can be
shortened.
-
Sampling processing
The A/D conversion for analog input values is
performed successively for each channel, and
the digital output value is output upon each
conversion.
The sampling processing time
changes depending on the number of
channels used (number of channels
set to A/D conversion enable) and
whether, with or without the
temperature drift compensation
function.
(a) Without temperature drift
compensation function (processing
time) = (number of channels used)
× 80 (µs /1 channel)
(b) With temperature drift
compensation function (processing
time)= (number of channels used)
× 80 (µs /1 channel) +160µs
Direct access processing
Sequence program separately from normal
sampling processing can specify channels to
carry out the A/D conversion, and outputting
the direct access request can perform direct A/
D conversion of specified channels.
When inputting channel specification with
sampling processing and direct access
processing simultaneously, the direct access
request is prioritized.
-
Q68ADV/I does not have [Direct
access processing] function.
Averaging processing
For each channel, A/D conversion values are
averaged for the set number of times or set
amount of time, and the average value is
output as a digital value.
The setting range is as shown below:
Averaging processing by the number of times:
4 to 62500
Averaging processing by time: 2 to 5000ms
-
Maximum and minimum
values hold function
The maximum and minimum values of the
digital output values are retained in the
module.
-
Temperature drift
compensation function
Errors arising from changes in the ambient
temperature of the module are automatically
compensated to improve conversion accuracy.
The temperature drift compensation function
can be performed at (A/D conversion time for
all channels) + 160µs.
-
Resolution mode
The resolution settings of 1/4000, 1/12000 or
1/16000 can be selected according to the
application.
The resolution mode setting is applicable to all
channels.
-
Online module change
A module change is made without the system
being stopped.
-
The CPUs corresponding to online
module replacement are process CPU
and redundant CPU modules.
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