Siemens SIMATIC S7-200 System Manual page 398

S7-200 Programmable Controller System Manual
Table 15-2 Expanded Description of Control and Status Fields
Field
AT Control (ACNTL)
Input - - Byte
AT Status (ASTAT)
Output - - Byte
AT Result (ARES)
Input/Output - - Byte
AT Config (ACNFG)
Input - - Byte
384
Description
MSB
7
0 0
EN - - Set to 1 to start auto-tune; set to 0 to abort auto-tune
MSB
7
W0 W1
W0 - - Warning: The deviation setting is not four times greater than the
hysteresis setting.
W1 - - Warning: Inconsistent process deviations may result in incorrect
adjustment of the output step value.
W2 - - Warning: Actual average deviation is not four times greater than
the hysteresis setting.
AH - - Auto-hysteresis calculation in progress:
0 - - not in progress
1 - - in progress
IP - - Auto-tune in progress:
0 - - not in progress
1 - - in progress
Each time an auto-tune sequence is started the PLC clears the warning bits and sets
the in progress bit. Upon completion of auto-tune, the PLC clears the in progress bit.
MSB
7
D
D - - Done bit:
0 - - auto-tune not complete
1 - - auto-tune complete
Must be set to 0 before auto-tune can start
Result Code:
00 - - completed normally (suggested tuning values available)
01 - - aborted by the user
02 - - aborted, watchdog timed out waiting for a zero crossing
03 - - aborted, process (PV) out-of-range
04 - - aborted, maximum hysteresis value exceeded
05 - - aborted, illegal configuration value detected
06 - - aborted, numeric error detected
07 - - aborted, PID instruction executed without having power
flow (loop in manual mode)
08 - - aborted, auto-tuning allowed only for P, PI, PD, or PID loops
09 to 7F - - reserved
MSB
7
0 0
R1 R0 Dynamic response
0 0 Fast response
0 1 Medium response
1 0 Slow response
1 1 Very slow response
DS - - Deviation setting:
0 - - use deviation value from loop table
1 - - determine deviation value automatically
HS - - Hysteresis setting:
0 - - use hysteresis value from loop table
1 - - determine hysteresis value automatically
0 0 0 0
W2 0 AH 0
Result Code
0 0 R1 R0
LSB
0
0 EN
LSB
0
0 IP
LSB
0
LSB
0
DS HS