GE GFK-0787B Noise Reduction Machine User Manual


 
8
8-12 Genius Modular Redundancy Flexible Triple Modular Redundant (TMR) System
User’s Manual – March 1995
GFK-0787B
Output Wiring for a 16-Circuit, 4-Block Group (continued)
Output Load Considerations for 16-Circuit 4-Block “H” Pattern
Redundant Output Groups
Minimum load: 100 milliamps
Maximum load: 2.0 Amps
Maximum inrush current: 10 Amps for up to 10 milliseconds
Maximum total load for block group: 15 Amps at 35 degrees C
Output Off Leakage Current: 2.0 milliamps
For Outputs to be Autotested:
Minimum pickup time: Greater than 20 milliseconds
Minimum dropout time: Greater than 7.5 milliseconds
Caution
Check the characteristics of each output device against the list above to
verify that it can be autotested and/or used in the 4-block output
group. Otherwise, critical output loads could be adversely affected.
Output Autotest and Pulse Testing
If output circuits are to be autotested, the loads will be subject to pulse testing, which is
an integral part of the output autotest sequence. Pulse testing verifies the ability of a
block’s outputs to change state with a short pulse that is not intended to affect the actual
load. Pulse testing occurs whether the output is in the On state or in the Off state by
executing one of two tests. These are the pulse ON–OFF–ON test and the pulse
OFF–ON–OFF test. The actual pulse width and the number of times a point is tested
depend greatly on its configuration, state (ON or OFF) and the type of load (or absence
of load) on the point. So, output circuits that are to be autotested must be able to
withstand On and Off pulse times that are discussed below. Each output device’s
characteristics should be checked against the list above to verify that it can be autotested
and/or used in the 4-block output group. The following Pulse Test descriptions refer to
Pulse Test operation of a block configured in the GMR mode only.
OFF–ON–OFF Test
The first ON pulse is for about 1.7mS. During this time, if the No Load diagnostic is
enabled, the current data is checked and recorded. After this time, the test turns the
point Off and the diagnostic, volts, and current data (if No Load is enabled) are checked.
If the correct voltage and/or current data is NOT reported, the time constant is increased
and the process repeats. If the correct voltage and/or current data is reported after any of
the pulses, the test is passed and no further pulsing of the point occurs. The maximum
number of pulses that can occur is 7, with a minimum duration of 1.7mS and a maximum
duration of 20mS. Also, these is a delay of approximately 5 to 15 mS until the same point
is pulsed again. These times depend greatly on the configurations of the other points.
ON–OFF–ON Test
Similar activity occurs for this test. The initial time a point is Off is about 5mS. The only
fault checked for in this case, however, is that the volts feedback agrees with the