Moore Industries STA - Page 65

www.miinet.comMoore Industries-International, Inc.
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User’s Manual
225-748-00P
August 2024
Programmable RTD, T/C, Ohms, mV and Potentiometer Safety Trip Alarm
STA
TPRG
SECTION 7
Configuration
The unit can be congured using the front panel buttons or PC Conguration Software as
described in this manual.
Note: While the system is in conguration mode the system is in an o󰀪ine mode and is not
performing the safety function.
Do not attempt to connect the STA Communications Cable to the STA while the output relays are
connected to a load.
After making any conguration changes, the user must validate the operation of the STA o󰀪ine to
ensure that the changes work safely, prior to putting it back into operation.
The following considerations and restrictions will apply when using the STA in a safety
application:
Trip Relay used as safety output: One or both trip alarms must be connected to the actuator/
equipment under control (EUC). The separate dedicated fault relay must either be
connected in series with the trip alarm OR connected to a separate indicator to only alarm
the fault while maintaining the process in normal operation. Refer to Figures 8.1 and 8.2 in
Section 8 for typical STA configurations.
Analog Output (AO) used as safety output: The STA may optionally be provided with an
analog output (AO) which can be used for connecting to displays, control systems, etc.
For STA units with V1.2 rmware or less, the AO is NOT certied for safety use and must not be
used as any part of a safety loop. The analog circuit is isolated from the STA safety circuits and
consequently its failure will not compromise the certied safety function of the STA.
For STA units with V1.3 rmware or later, the AO is certied for safety use and can be used in the
safety path. Refer to Figures 8.4 and 8.5 in Section 8 for typical congurations.
The AO must be configured as follows: The AO is a current output set at 4 to 20mA. The AO
is set to fail low (fail high is a non fail-safe condition when power is lost). The logic solver
is either configured to detect a ‘fail low’ condition for SIL1 applications (anything less than
4.0mA is detected as a fault) or a `fail windowed’ condition for SIL2 applications (anything
outside the 4-20mA range is detected as a fault). The fault alarm relay is used by the logic
solver to detect failures.
Note: When conguring Out of Range for STA units with rmware V1.5 or later, the Out of
Range value must be congured for 2% or less (default setting is 1%).
High Availability Configuration
(Figures 8.1 & 8.2)
Separating the process and fault loads increases availability but its use must be authorized only
after a careful hazard and operability study involving suitably qualied persons.
Warning: With this conguration, an internal STA fault would not trip the EUC.
Sensor Types
The STA is designed for use with a wide variety of inputs. It is the end user’s responsibility to
ensure that the chosen sensor is capable of achieving the required loop SIL.