BRUEL & KJAER VIBROCONTROL 8000 - 17.4 Using Channel Input Blocks; 17.4.1 Channel Input with ‘Or’

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17.4 Using Channel Input Blocks
17.4.1 Channel Input with ‘Or’
Channel Input blocks (Figure 17-10) allow you to select the channel, measurement, and alarm status
to apply to Boolean logic. To connect the blocks, select the black square and drag the mouse over to
the input socket on the next block.
Figure 17-10) Channel Input block (or logic)
Table 17-10 shows an example that requires one channel to be in Alert before the relay will trip.
1
2
3
4
5
Or
Channel 1
Alert
Fault
Bypass
Fault
Bypass
Channel 2
Ok
Ok
Ok
Fault
Bypass
Relay Active True False False False
False
Table 17-10) ‘Channel Input’ block, ‘Or’ logic
Checking the ‘Fault Votes True’ checkbox causes the block to evaluate to True when the channel is
faulted (See Table 17-11). This scenario increases the potential for false trips; Use this selection with
caution.
1 2 3 4 5
Or
Channel 1
Alert
Fault
Bypass
Fault
Bypass
Channel 2
Ok
Ok
Ok
Fault
Bypass
Relay Active True True False True
False
Table 17-11) ‘Channel Input’ block, ‘Or’ logic, Fault Votes True
The ‘Bypass Votes True’ option causes the block to evaluate to True when the signal channel is
bypassed. This option is not recommended. See section 6.6 Use Channel Bypass Appropriately.