Rockwell Automation T8094 8000 Series TMR System Safety Manual - Manual (Page 108)

SAFETY MANUAL
D oc N umber T8094
I ssue 27 – June 2013
Page 87 of 103
this, the migrated application must use triggered application cycles with an interval equal
to or greater than the required settling time.
5. You must disable the Trusted TM latent fault detection (LFD) feature for outputs
connected through the CS300 equipment. This will prevent spurious Trusted TM fault
reports.
6. You must do an analysis of the safety instrumented functions to find out how frequently
the autotests must run. Then configure the function blocks to do the tests when they are
necessary
.
7. The migrated application must have a mechanism to schedule the test sequences at a
user-definable time of day and rate.
8. When the function blocks find a fault, they latch (hold) it. The migrated application must
have a mechanism to let the user reset the records of latched faults after a fault is
removed. The mechanism can reset faults individually, or reset multiple faults with one
action.
9. The replacement of CS300 I/O modules must be done only when the test sequences
are not running. The migrated application must provide a suitable indication so that
maintenance operators know when they can replace a module.
9.10.4.2 Testing Digital Inputs
If a safety integrated function (SIF) relies on one or more CS300 digital inputs, you
must use the function blocks to do tests on the inputs for stuck on / stuck off
conditions. You will use at least one ITSTM function block, to schedule the tests for the
inputs, and several DIPT function blocks – one DIPT for each digital input.
The DIPT does tests on simplex input channels or duplex input channels, but not both
at the same time. If it is necessary to do tests on simplex and duplex input channels in
the same system, you must use at least two sets of DIPT function blocks – one for
simplex (as illustrated above) and one for duplex (as shown by the dotted lines above).