Omron CRT1 - 10-2008, Operation Manual

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Overview of Analog I/O Slave Units Section 6-1
6-1 Overview of Analog I/O Slave Units
This section provides an overview of Analog I/O Slave Units, including details
on functions and setting methods for each Unit.
6-1-1 Analog I/O Slave Units
Analog I/O Slave Units can use a variety of functions, such as scaling and
peak/bottom hold functions. Analog Input Units can also internally perform
math on analog input values, which previously required ladder programming
at the host PLC.
Analog data can be selected from the six values obtained from math opera-
tions and allocated as I/O in the Master Unit in combination with Generic Sta-
tus Flags or other status information. The CX-Integrator can be used to easily
allocate status information, monitor and set unique Analog I/O Slave Unit
functions, and monitor operation.
6-1-2 List of Data Processing Functions
The following tables list the data processing functions that can be used with
Analog I/O Slave Units. Refer to
6-4 Analog Input Slave Units and 6-5 Analog
Output Slave Units for details on functions and setting methods.
CRT1-AD04 Analog Input Slave Unit
Function Details
Moving average Calculates the average of the past eight analog input val-
ues, and produces a stable input value even when the input
value is unsteady.
Setting the number of
AD conversion points By reducing the number of input conversion points, the con-
version cycle speed can be increased. For details, refer to
6-4-3 Calculating the Conversion Cycle.
Scaling Performs scaling.
Scaling allows conversion of values between 0 and 6,000
into values using the industry unit required by the user. It
reduces the number of operations requiring ladder program-
ming in the CPU Unit. Scaling also supports an offset func-
tion for compensating for mounting errors in sensors and
other devices.
Peak/bottom hold Holds the maximum and minimum analog input values.
Top/valley hold Holds the top and valley values for analog input values.
Rate of change Calculates the rate of change for analog input values.
Comparator Compares the analog input value or an analog value after
math processing (value for peak, bottom, top, valley, rate of
change) with the four set values HH, H, L, and LL, and indi-
cates the result with the Analog Status Flags.
Disconnected line
detection Detects disconnections of analog inputs. (Valid only for the
input ranges 4 to 20 mA and 1 to 5 V)
User adjustment Adjusts the input when an offset occurs in the input voltage
or current.
Cumulative counter Calculates an approximation to the integral of analog input
values over time.