Rockwell Automation 1715-OF8I Redundant I/O System User Manual - Manual (Page 228)

228 Rockwell Automation Publication 1715-UM001C-EN-P - March 2014
Chapter 7 Using SIL 2 Add-On Instructions with 1715 Redundant I/O Modules
Add-On Instruction Outputs The Add-On Instructions generate these outputs.
Reconciled_Input_Data If the Add-On Instruction examines the check data and determines that the input
data is valid, the data in this tag is a duplicate of the original data received from the
input module.
If the Add-On Instruction examines the check data and determines that the data is
not valid, the safe state values are substituted in the Reconciled Input Data tag.
This is the input data to be used in the logic program.
Input_Data This is the raw data from the 1715 module. You must point to this tag when
configuring the Add-On Instruction.
Module_RPI Enter this value manually from the module properties. Use the exact value to
optimize system bandwidth.
Reset The reset function requires a LO to HI transition of this tag. It resets faults and directs
the ControlLogix controller to stop transferring the safe state data and start
transferring the actual data, provided that the SIL 2 check data is verified. This tag is
also sent to the 1715 output modules so that outputs can be reset from the safe
state.
Table 44 - Add-On Instruction Inputs
Input Description
Table 45 - Add-On Instruction Outputs
Output Description
Data Valid This value is HI if the Add-On Instruction is moving the input data to the Reconciled
Input Data tag without substituting safe state values. This value remains HI if packets
are being discarded but the CRTL has not timed out. During this time the reconciled
input data is not updated and data may no longer be current. If the CRTL expires, the
safe state values are placed into the Reconciled Input Data tag.
Valid Data Being Received If valid data is being received from the module this output is HI regardless of whether
this data is being moved to the Reconciled Input Data tag. This output must be HI
before you perform a SIL 2 Reset to begin moving actual data to the Reconciled Input
Data tag.
This output goes LO if a valid data packet is not received for a time equaling three (3)
Module RPIs. If this output is toggling LO, verify that the RPI entered into the Add-On
Instruction matches the actual module RPI. The periodic task rate can also have an
effect on this output. If the periodic task rate is too high, then the packets may not be
processed often enough. See the 1715 SIL 2 task recommendations in this manual for
configuration recommendations.
Reset Tiedown Fault If the reset button is HI for longer than 3 seconds, a tiedown fault is declared. The
fault is cleared when the reset button transitions to LO.
CRC Error CRC Error will be HI if the accumulated error count (for detected CRC errors) has
exceeded the allowable threshold.
Duplicate Sequence Number If the sequence number is a duplicate, data is discarded as invalid and this output is
set HI to indicate the reason.
Low Sequence Number If the sequence number is lower than expected, data is discarded as invalid and this
output is set HI to indicate the reason.
High Sequence Number If the sequence number is higher than expected, data is discarded as invalid and this
output is set HI to indicate the reason.
Source IP Error
If any of these check data values, described on page 227 , do not match the values in
the 1715 module configuration, data is declared invalid and discarded. The
appropriate output is set HI to indicate the reason.
Source Slot Error
Destination IP Error
Destination Slot Error
Variant ID Error
Module Connection Status This output is set LO if the Add-On Instruction detects a connection loss. Input data is
declared invalid and the CRTL is not reset. When the connection is re-established, this
output is set HI.