6.22.6 PID Troubleshooting
For some systems, the Parameter values derived from the Auto-tuning process will be less
than optimal. If Auto-Tuning derives such parameter values, the user should refer to the
descriptions above for each relevant parameter (K
P
, T
I
, and T
D
) or see the following guide to
adjust these parameters.
Response when K
P
is decreased:
The PV rises slowly, stabilizes slowly with no overshoot.
Response when T
I
is increased:
The PV stabilizes slowly with less searching (overshoot and undershoot) for the SV.
Response when T
D
is increased:
The PV stabilizes quickly. There is more searching (overshoot and undershoot) for the SV.
6.22.7 Error Codes
Error Codes are reported by the PID Function Block via the string output pin. The error code
byte consists of 8 error flags, but only the lower 6 bits are functional. An error code value of
zero means there is no error.
Table 6.30:
Bit Content State of processing
b0 Sampling time < (system) scan time
Filtered PV change overflow
MR-RB136-4
FX1S-14MR-D
FX1N-40MT-D
MR-E200AG
AJ65MBTL1N-16T
Q170ENCCBL2M
MR-J3-10B
HA-LFS22K1M
MR-ESCBL10M-H
MR-JACN15K
MR-PWCNS4
MR-J3ENSCBL5M-L
FX1NC-16MT
FX3U-64MT/DS
MR-J3ENSCBL30M-L
Q2MEM-1MBS
MR-J2S-70A
MR-J2S-100A4
MR-J2S-55KB4
Q170BDCBL10M
QD75M1
FX3G-60MR/ES-A
FX3G-24MR/ES-A
Q2MEM-16MBA
FX3U-485ADP-MB
AC12MX
Q173J2B4CBL1M
MR-J3ENSCBL5M-H
MR-E70AG
A3NMCA-56
FX2NC-96MT
MR-J2S-350B4
MR-PWCNS5
MR-JHSCBL10M-L
FX3UC-32MT-LT-2
GT1665M-STBD
MR-E10A
MR-JHSCBL20M-L
FX3U-232ADP-MB
MR-J2S-15KA
HF-MP43B
Q172HBCBL1M-B
FX3G-24MT/DSS
MR-J3BAT
GT1685M-STBA
FX1S-14MT-001
FX1N-EEPROM-8L
MR-ENECBL2M-H
MR-JCCBL20M-H
Q170CDCBL10M