Siemens LMV5 Quick Start Manual page 99
Hide thumbs
Also See for LMV5:
- Technical instructions (374 pages) ,
- Basic documentation (278 pages) ,
- Manual (39 pages)
Advertisement
Menu Path
Parameter
StandardParam
Params & Display>
Load Controller>
Controller Param>
ContrlParam List
P-Part
I-Part
D-Part
LMV5 QSG Rev 4
U = User
O = OEM
S = Service
These are "canned" values for the PID loop in the internal load controller as well as and option to use values
found during adaptation (autotune). Adaptation (autotune) is not performed with this parameter, but the PID
results of an adaptation (autotune) can be used by selecting adaptation.
Values are labeled: very slow, slow, normal, fast, and very fast. When any one is selected "canned"
values will be assigned to P I and D that will determing how the load controler responds.
Note that every time this parameter is viewed, current will be shown as "XXX" and new will show "very slow".
This does not mean that the load controller is using very slow PID values. The "StandardPararm" screen just
shows "very slow" since it the first option in line.
When very slow is selected, the P value is small (small proportional band), and values for I and D are longer
(greater number of seconds), meaning there is less intergral and derivitive action. If very fast is selected, the
P value is large and the I and D are short, meaning that the propotional band is large and there is a large
amount of intergral and derivitive action.
Recommendations: normal will work well for most situations
very slow
P =
3.4 %
normal
P =
6.4 %
very fast
P = 42.5 %
U
P part of the PID loop, is the proportional band around the setpoint, in % units. This % is based on the
measured range or span of attached sensor. If normal response was selected above, then this will be 6.4%.
If "canned" values are not used 10% is usually a good starting point
If canned values are not used, 10% is usually a good starting point.
Range = 2 to 500% Def = 15% Typ = 6.4%
I part of the PID loop, is the integral function that is applied to the behavior of the process variable (boiler
temp. or press). Basically it counteracts fast decreases in the process variable by increasing boiler load even
faster than the P alone. If normal response was selected above, this will be 136 seconds. This can also be
deactivated by setting this to 0 sec. If "canned" values are not used, 80 seconds is usually a good starting
point.
Range = 0 to 2000sec Def = 320sec Typ = 136 sec
D part of the PID loop. D is the derivative function that is applied to the behavior of the process variable
(boiler temp. or press). Basically it counteracts fast increases in the process variable by decreasing boiler
load even faster than the P alone. If normal response was selected above this will be 24 seconds. This
setting must always be at least 1/5 of the setting for I or the PID loop may be unstable. Setting this to 0 sec is
also possible, deactivating this part of the loop and leaving a PI loop. If "canned" values are not used 15
seconds is usually a good starting point.
Range = 0 to 1000sec Def = 40sec Typ = 24sec
Sec 4 Pg 43
Descriptions / Notes
I = 273 seconds
D = 48 seconds
I = 136 seconds
D = 24 seconds
I =
68 seconds
D = 12 seconds
60-62
www.scccombustion.com
Advertisement
