Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 183

■SV variation rate & high/low limiter
This function block checks the variation rate and high/low limits to the set value every control cycle (CT).
• Variation rate limiter
The SV variation rate high limit value input in percentage is converted into an engineering value, and the processing will be
performed.
DSVL  DSVLT (DSVL: SV variation rate high limit value, DSVLT: SV variation rate high limit value converted into an
engineering value)
Condition
|SV - SVC|  DSVLT
SV - SVC > DSVLT
SV - SVC < -DSVLT
SV: Setting value (target), SVC: Setting value (current)
If DSVLI of the disable alarm detection 2 or ERRI of the disable alarm detection is TRUE, DSVLA will be FALSE.
• High/low limiter
When SVLMT_EN is TRUE
Condition
Variation rate limiter result > SH
Variation rate limiter result < SL
SL  Variation rate limiter result  SH
If SVLI of the disable alarm detection 2 or ERRI of the disable alarm detection is TRUE, SVLA will be FALSE.
If SVHI of the disable alarm detection 2 or ERRI of the disable alarm detection is TRUE, SVHA will be FALSE.
The high/low limiter result is stored in SVC (setting value (current)).
When SVLMT_EN is FALSE
The variation rate limiter result is stored in SVC (set value (current)).
■Engineering value inverse conversion
This function block converts the setting value (SV) of an engineering value into a manipulated value in percentage (%).
MV(%) = 100/(RH - RL)  (SV - RL)
RH: Engineering value high limit
RL: Engineering value low limit
SV: Setting value
MV: Manipulated variable
■Tracking processing
When tracking is requested by a subsequent FB through CASOUT_T, this function block converts the value written to the MV
into an engineering value and performs tracking to SV and SVC.
■Loop stop processing
When the stop alarm (SPA) of the alarm (ALM) or the tag stop (TSTP) of the monitor output buffer (DOM) is TRUE, this
function block performs the following processing.
• The control mode is automatically switched to MANUAL.
• When DVLA of the alarm (ALM) has occurred, the DVLA is reset. When DSVLA, SVLA, or SVHA of the alarm 2 (ALM2) has
occurred, the DSVLA, SVLA, or SVHA is reset.
• No alarm is detected in the deviation check or SV variation rate & high/low limiter processing.
Variation rate limiter result
SV
SVC + DSVLT
SVC - DSVLT
High/low limiter result
SH
SL
Variation rate limiter result
Alarm 2 (ALM2) SV variation rate limit
alarm (DSVLA)
FALSE (Reset)
TRUE (Detected)
TRUE (Detected)
Alarm 2 (ALM2)
SV low limit (SVLA)
FALSE (Reset)
TRUE (Detected)
FALSE (Reset)
9.9 Manual Setter (M+P_MSET_)
SV high limit (SVHA)
TRUE (Detected)
FALSE (Reset)
FALSE (Reset)
9 I/O CONTROL
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