HARDWARE MANUAL Document reference MAMPS-HW/E
VM600 machinery protection system (MPS) Edition 18 - March 2022
4-18
Alarm monitoring
MPC4 / IOC4T CARD PAIR
4.6.3 Adaptive monitoring
This technique allows the Alert and Danger levels to be dynamically set as a function of an
adaptive parameter. The adaptive parameter can be:
• Speed, as measured on one of the two “local” speed inputs (that is, from the card pair in
question).
• Any other control/process parameter such as load or water head measured on one of the
two “local” speed inputs (that is, from the card pair in question), for example, by using an
external current loop or voltage to frequency converter device.
NOTE: When using an external analog signal to frequency converter device, the
measured “speed” is proportional to the control/process parameter to be used
for the adaptive monitoring.
Adaptive monitoring is particularly useful for run-ups and coast-downs where the adaptive
parameter is speed.
The alarm levels (Alert and Danger) are multiplied by a coefficient depending on the
parameter (in this case, speed), as illustrated in Figure 4-8. For example, for the nominal
speed of the machine (after s6), this coefficient is equal to 1.0. However, in the speed range
s1 < speed < s2, the Alert and Danger levels are multiplied by 1.2 in order to avoid a machine
shutdown when the machine crosses its first critical speed (see Figure 4-8).
NOTE: Multiplier coefficients are always applied to Danger+ and Alarm+ (high) levels.
Multiplier coefficients are applied to Danger− and Alarm− (low) levels only when
their values are negative. When they are positive and the multiplier coefficient is
not equal to 1.0, both Danger− and Alarm− are disabled.
Up to 10 parameter ranges (for example, speed) can be defined (s1, s2 and so on, in
Figure 4-8).
Up to 10 multiplier coefficients can be configured (for example, 0.5, 0.8, 1.2 and so on, in
Figure 4-8).
These coefficients can be chosen in the range 0.1 to 5.0, in steps of 0.1.
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