BRUEL & KJAER VIBROCONTROL 8000 - 17.3.3 For All (1 and 2 and 3…) Logic Block; 17.3.3.1 Thrust Channel Example

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17.3.3 For All (1 and 2 and 3…) Logic Block
The "For All" block performs the logical AND function. All channels in the selected asset group (“With:
The Rack”, or “With: Motor A”) are included in this logic.
Channel Status
(All) Alert/Danger
Fault
Bypass
Logic block output
True
-
-
Table 17-4) Truth table For Any Channel (1 or 2 or 3…) logic block
This block performs as follows:
1. Logical AND function between all channels in the selected asset group. For example: (1X and
1Y and 2X and 2Y and 3X etc.) All channels must evaluate to true for the output of the block to
be true.
2. A Faulted or Bypassed channel does not vote ‘True’ or ‘False’. It is removed from the logic.
For example, If Channel X is bypassed (or in fault) the relay logic (1X and 1Y and 2X and 2Y)
would become (1Y and 2X and 2Y).
17.3.3.1 Thrust Channel Example
A common use of the ‘For All’ logic block is a Thrust channel pair voting two-out-of-two (2oo2).
Table 17-5 shows several possible scenarios of the logic block in Figure17-7.
Figure 17-7) Thrust channel, ‘For All (1 and 2 and 3)’ logic block
Notice that Thrust channels do not have a Fault state. A critical thrust event on a machine may
damage the thrust probes; to protect the machine, thrust probes will “Fault to Danger”.
1 2 3 4 5
Thrust 1A Danger Danger Fault (Danger) Ok Bypass
Thrust 1B Danger Fault (Danger) Fault (Danger) Fault (Danger) Bypass
Output True True True False False
Table 17-5) Thrust channel, ‘For All’ logic block, scenarios