Specifications

Publication 1794-SG002D-EN-P - May 2012
Select FLEX I/O Modules 35
FLEX I/O Analog,
Thermocouple and RTD
Modules
Choose analog, thermocouple, or RTD I/O modules when you need:
• Individually configurable channels allow the module to be used with a
variety of sensors.
• On-line configuration. Modules can be configured in RUN mode using
programming software or the control program. This allows you to change
configuration while the system is operating.
• Selectable input filters on many modules allow you to select from several
different filter frequencies for each channel that best meets the
performance needs of your application. Lower filter settings provide
greater noise rejection and resolution. Higher filter settings provide faster
performance. Note: Isolated analog modules have four filter selections; the
thermocouple module has ten; and the combined RTD/thermocouple module
has eight.
• Ability to direct output device operation during an abnormal
condition.
Each channel of the output module can be individually configured to hold
its last value or assume a user-defined value on either a run-to-program or
run-to-fault condition. This feature allows you to set the condition of your
analog devices, and therefore your control process, which may help to
ensure a reliable shutdown.
• Selectable response to broken input sensor. This feature provides
feedback to the controller that a field device is not connected. This allows
you to specify corrective action based on the channel condition.
• Single-ended or differential inputs depending on module. Analog
modules have single-ended inputs while isolated analog and temperature
modules have differential inputs. Single-ended voltage sensors reduce
costs. Differential inputs are more expensive, but are typically more noise
immune.
• Over- and under-range detection and indication are available with most
modules. This eliminates the need to test values in the control program.
While standard analog modules have limited diagnostics, temperature and
isolated analog modules provide over-range, under-range, and wire-off
diagnostics with alarm bits.
• On-board scaling is performed by the temperature modules and is user
configurable for either °C, °F, °K, Ohms, or mV. This eliminates the need
to scale the data in the user program.
• Accuracy and resolution varies by module and the associated
application. Specifications are given for each module at it's operational
conditions.
• Internal calibration is performed in the analog modules (1794-IE8,
1794-OE4, and 1794-IE4XOE2). User calibration is recommended
(yearly) for isolated analog and temperature modules. All modules come
factory calibrated.