Limit monitoring
The block monitors the process value
PV_In
for limits. The value is cyclically integrated into the
process image of the controller. The limits are configured on the block.
You can monitor the process value
PV_In
for the following high and low alarm and warning
limits:
●
PV_AH_Lim
: Limit for high alarm
●
PV_AL_Lim
: Limit for low alarm
●
PV_Hyst:
Hysteresis
●
PV1_WH_Lim
: Limit for high warning
●
PV1_WL_Lim
: Limit for low warning
The result of limit monitoring is returned at the following interconnectable output parameters:
●
PV_AH_Act
= 1: Limit for high alarm reached or exceeded
●
PV_AL_Act
= 1: Limit for low alarm reached or undershot
●
PV_WH_Act
= 1: Limit for high warning reached or exceeded
●
PV_WL_Act
= 1: Limit for low warning reached or undershot
Monitoring is always enabled using the input parameters:
●
PV_AH_En
= 1: Monitoring of the high alarm limits
●
PV_AL_En
= 1: Monitoring of the low alarm limits
●
PV_WH_En
= 1: Monitoring of the high warning limits
●
PV_WL_En
= 1: Monitoring of the low warning limits
The corresponding message is suppressed using the parameters:
●
PV_AH_MsgEn
= 0: Alarm (high) messages are suppressed
●
PV_AL_MsgEn
= 0: Alarm (low) messages are suppressed
●
PV_WH_MsgEn
= 0: Warning (high) messages are suppressed
●
PV_WL_MsgEn
= 0: Warning (low) messages are suppressed
You can define a hysteresis (
PV_Hyst
) for the limits, for example to suppress signal flatter. You
can also modify the limits and hysteresis via the faceplate.
Gradient monitoring
The gradient
PV_Grad0
is calculated by means of a delay function configurable
using
LagTime
. During calculation of the gradient, jumps in the input value
PV_In
are
smoothed.
The peak values of the gradient are output in the output parameters
PV_GradNP0
(negative
gradient) and
PV_GradPP0
(positive gradient). These are reset when the operator enters the
corresponding command for resetting.
SITRANS LU HART
17.1 SitrLuHA
SITRANS Library for PCS 7
782
Function Manual, 05/2019, A5E35351976-11
Summary of Contents for SITRANS PCS 7
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Page 418: ...SITRANS P 10 2 SitraPDr SITRANS Library for PCS 7 418 Function Manual 05 2019 A5E35351976 11 ...
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