Hart Pass-Through; Actuator Configurations; Rockwell Automation Publication Icstt-Rm446N-En-P - April - Allen-Bradley AADvance T9110 Safety Manual

Chapter 4 AADvance Functional Safety System Implementation

Actuator Configurations

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ATTENTION: HART Pass-Through should be disabled if the field devices do
not have locked configuration, or if the device status is not monitored and
alarmed to prevent accidental or unauthorized changes to field device
configuration.
ATTENTION: HART devices have custom data which is provided in response
to HART command #03, the specific data for each device type must be used in
accordance with the device manufacturers published recommendations.

HART Pass-Through

AADvance also supports a HART Pass-Through feature. This gives
AADvance the ability to pass HART data between an external Asset
Management System (AMS) and Field Devices. This is strictly a pass-through
mechanism using a dedicated AADvance HART DTM. This pass-through
capability can however be enabled or disabled under application control.
ATTENTION: If HART Pass-Through is enabled on a safety loop, then either
the field device shall have the facility to lock the configuration on the field
device itself or the HART Pass-Through function shall be disabled by the
application program during normal operation when HART communication is
not required.
ATTENTION: The device status must be monitored and alarmed if HART Pass-
Through is enabled.
ATTENTION: The software package used to monitor and configure the field
device using HART Pass-Through shall be evaluated to ensure that it is
suitable for use with safety devices.
In safety critical applications using a single actuator, it is important that the
actuator failure modes be predictable and well understood, so that there is little
probability of a failed actuator not responding to a critical process condition.
In such a configuration, it is important that the actuator be tested regularly,
either by dynamic process conditions that are verified in the AADvance
system, or by manual intervention testing.
The function of a signal shall be considered when allocating the module and
channel within the system. In many cases, redundant actuator configurations
may be used, or differing actuator types can provide alternate control and
mitigation possibilities. Plant facilities frequently have related signals; in these
cases it is important to ensure that failures beyond the system's fault-tolerant

Rockwell Automation Publication ICSTT-RM446N-EN-P - April 2018