Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 312

■High/low limit check
This function block performs the high/low limit checks.
Control mode
MAN, CMV
AUT, CAS, CSV
MVn: MV output
MH: Output high limit value
ML: Output low limit value
MHA: Output high limit alarm
MLA: Output low limit alarm
■Disable alarm detection
This function block sets whether to detect alarms (ALM) or not in the high/low limiter processing.
Item
Disable alarm detection by setting tag data
Disable alarm detection by control mode selection
Disable alarm detection by loop stop processing
■Loop stop processing
When the stop alarm (SPA) of the alarm (ALM) is TRUE, this function block performs the following processing.
• Outputs (MVP) are held.
• The control mode is automatically switched to MANUAL.
• When MHA or MLA of the alarm (ALM) has occurred, the MHA or MLA is reset.
• No alarm is detected in the variation rate & high/low limiter processing.
Even when an operation constant "Number of points" (PTNO) of tag data is 0, the same processing as loop
stop processing is performed.
10 LOOP CONTROL OPERATION
310
10.24 Program Setter (M+P_PGS)
Description
MV
n
MVpgs
• MVpgs is not fixed with MH or ML even though MVn is equal to or greater than MH or MVn is equal to or
smaller than ML.
• No MHA or MLA of the alarm (ALM) is detected even though MVpgs is equal to or greater than MH or
MVpgs is equal to or smaller than ML.
MV
n
MVpgs
MHA occurs
• MVpgs is fixed with MH or ML when MVn is equal to or greater than MH or MVn is equal to or smaller than
ML. (When MVn has been programmed like the broken lines in the above diagram, MVpgs will be fixed as
the solid lines in the above diagram and output.)
• MHA or MLA of the alarm (ALM) will occur when MVn is equal to or greater than MH or MVn is equal to or
smaller than ML.
Disable alarm detection processing
If the following bits in the disable alarm detection (INH) are TRUE, MHA or
MLA of the alarm (ALM) will not be detected.
• ERRI
• MHI
• MLI
In the MAN or CMV mode, MHA and MLA of the alarm (ALM) are reset and
MHA or MLA will not be detected.
Page 310 Loop stop processing
MV
n+1
MV
n+2
MV
n+1
MV
n+2
MHA occurs
MH
ML
MV
n+3
t
MH
ML
MV
n+3
t
t