Rockwell Automation T8110B/T8110 Trusted TMR Processor - Manual (Page 28)

Trusted
TM
TMR Processor T8110B/T8110
Issue 18 Feb 08 PD-T8110B/T8110 28
The central modules also contribute to the Input Module and Output Module times. The impact to each
is factored in on a per-module basis, and is included in the respective calculations as the “Scan
Factor”.
Module Type No. Installed Time
Standby TMR Processor Module x 1 ms
TMR Interface Module x 0.8 1
Communications Interface Module
x 1.5 ms1
Scan Factor
4.7.2. Input Modules
The Input Module time is based on the number of Trusted TM High Density Input modules. The time
calculations are independent of the number of channels on each module (i.e. a 60 channel DUAL
module has an equivalent input module time as a 40 channel TMR module). The Input Module time is
calculated by adding the “Scan Factor” to a constant, then multiplying this by the total number of High
Density Input modules.
Factor No. Input Modules Input Total
( + 4.5 ms ) x
4.7.3. Output Modules
The Output Module time is based on the number of Trusted TM High Density Output modules. The time
calculations are independent of the number of channels on each module (i.e. a 32 channel 120Vdc
Digital Output module has an equivalent output module scan time as a 40 channel Analogue Output
module). The Output Module time is calculated by multiplying the “Scan Factor” by 2, adding the result
to a constant, then multiplying by the total number of High Density Output modules.
Scan Factor No. Output Modules Output Total
( ( x 2 ) + 7.6 ms ) x
While the Output Module time may seem disproportionately long when compared to the Input Module
time based solely on the number of modules, Output modules are accessed twice during each cyclical
period: once to provide input data to the application (such at channel state, voltage, and current), and
again when controlling the outputs themselves.
2
1 The actual values used in calculating the “Scan Factor” for the TMR Interface and Communication
Interface Modules can vary. The values presented in the above table are correct for the default
configuration, but can be adjusted downward to tune system performance.
2 The default configuration is for all outputs to be updated each scan, irrespective of a change of state
(or value). If the Trusted system is configured to update outputs only when they change, the Output
Module time calculation is as follows: [ (Scan Factor + 4.5 ms) x No. Output Modules ] + [ (Scan Factor
+ 3.1) x DeltaOM ], where “DeltaOM” represents the average number of Output Modules with at least
one channel that will change state (or value) with each composite scan time and is at least 1 for any
system that contains at least 1 Output Module.