Manual 35086
ProTech-GII with Math Functions
Woodward
64
If the ProTech-GII’s acceleration redundancy manager is configured for use then each module uses its
local calculated acceleration rate (calculated from the local speed signal) and the shared acceleration
rates from the other two modules to select/vote the signal to use in its over-acceleration detection logic.
The acceleration redundancy manager can be configured to vote the median highest or lowest
acceleration rate signal to use in its over-acceleration detection logic, and can be configured to change its
voting logic based on the number of healthy speed probes/signals.
If the module’s Acceleration Redundancy Manager is configured for use then each module uses its local
derived acceleration signal and the shared acceleration signals from the other two modules to select/vote
the signal to use in its over-acceleration detection logic. Each module’s Acceleration Redundancy
Manager can be configured as follows depending on the number of used or healthy speed signals:
1. Three used/healthy speed/acceleration signals condition (Base Function):
a. Median signal (middle signal)
b. Highest
signal
c. Lowest
signal
2. Two used/healthy speed/acceleration signals condition (Fallback Function):
a. Highest
signal
b. Lowest
signal
3. One used/healthy speed/acceleration signal condition (Two Inputs Failed Action):
a. Used/sensed healthy speed/acceleration signal
b. Issue a trip command
The front panel monitoring of this block displays the configured values, actual values and the active signal
selection mode (median, high signal select, low signal select). See Monitor Acceleration Redundancy
Monitor in Chapter 4. Actual data values can also be monitored over Modbus, see Chapter 9.
Speed Diagnostics
The speed diagnostic logic provides the speed lost and speed probe open wire diagnostics. See figures
3-1 & 3-2.
Speed Lost
Speed is monitored for a sudden loss of speed signal. The fault action for this diagnostic can be set to
trip, alarm, or turned–off (not used). This diagnostic is triggered when speed drops out (zero detected)
while the previous (4ms) speed sample was above the user-configured threshold (default is 200rpm).
Once detected, a speed lost condition will remain true until cleared by a reset or until speed is detected.
Open Wire
When the speed probe type is passive, then the local speed signal input is monitored for an open wire
condition. The fault action (alarm vs trip) varies with the speed redundancy setup. When detected and
speed redundancy is used, an Open Wire Alarm will be issued. If speed redundancy is not used, then a
trip will be issued.
Start Logic
The start signal is generated by selecting the START button on the module front panel or by closing the
dedicated Start contact input. The start signal is edge- triggered and re-selecting Start will reset the timer.
Released