bobbuilder
Member
I'm doing a PLC5 -> Ctrllgx conversion, the PLC5 prog. contains a few PID instructions. One uses a PD ctrl. block, which converts fine, the others use integer ctrl. blocks, which don't convert properly. I've never used an integer block for a PID and there are some differences between the two that I'm not too sure about. To make things simple lets ignore the ControlLogix, and say I want to change the PID instruction in the PLC5 from an integer ctrl. block to a PD ctrl. block.
Integer block values (existing):
Equation = ISA
Mode = Auto
Error = SP-PV
Output Limiting = no
Set Output Mode = no
Setpoint Scaling = no
Derivative Input = PV
Deadband Status = 0
Upper CV Limit Alarm = 0
Lower CV Limit Alarm = 1
Setpoint Out of Range = 0
PID Done = 0
PID Enabled = 0
Feed Forward = 0
Max Scaled Input = 1500
Min Scaled Input = 0
Deadband = 0
Set Output Value % = 40
Upper CV Limit % = 100
Lower CV Limit % = 0
Scaled PV Value = 0
Scaled Error = 0
Current CV % = 0
Setpoint = 0
Proportional Gain = 65
Reset Time = 10
Derivative Rate = 0
Loop Update Time = 25
Last State = resume
Here's what I'm thinking for the new block:
new PD block values:
Configure tab
PID Equation = Dependant
Derivative of = PV
Control Action = SP-PV
PV Tracking = No
Update Time = 0.25
Cascaded Loop = No
Engineering Unit Maximum = 1500
Engineering Unit Minimum = 0
Input Range Maximum = 4095
Input Range Minimum = 0
Output Limit High % = 100
Output Limit Low % = 0
PV Alarm High = 0
PV Alarm Low = 0
PV Alarm Deadband = 0
(+) Deviation Alarm = 0
(-) Deviation Alarm = 0
Deviation Alarm Deadband = 0
Status tab
Setpoint = xxx
PID Initialized = no
A/M Station Mode = auto
Software A/M Mode = auto
Status Enable = 0
Proportional Gain = 0.65
Integral Gain = 0.1
Derivative Time = 0
Deadband = 0
Output Bias % = 0
Tieback % = 0
Set Output % =40
Mostly the thing that bothers me is the "max/min scaled input" from the integer block. The description in the help file is kinda vague on that one, not sure if it translates to the "max/min eng. unit" or the "max/min input range"...
Any help would be much appreciated...
Integer block values (existing):
Equation = ISA
Mode = Auto
Error = SP-PV
Output Limiting = no
Set Output Mode = no
Setpoint Scaling = no
Derivative Input = PV
Deadband Status = 0
Upper CV Limit Alarm = 0
Lower CV Limit Alarm = 1
Setpoint Out of Range = 0
PID Done = 0
PID Enabled = 0
Feed Forward = 0
Max Scaled Input = 1500
Min Scaled Input = 0
Deadband = 0
Set Output Value % = 40
Upper CV Limit % = 100
Lower CV Limit % = 0
Scaled PV Value = 0
Scaled Error = 0
Current CV % = 0
Setpoint = 0
Proportional Gain = 65
Reset Time = 10
Derivative Rate = 0
Loop Update Time = 25
Last State = resume
Here's what I'm thinking for the new block:
new PD block values:
Configure tab
PID Equation = Dependant
Derivative of = PV
Control Action = SP-PV
PV Tracking = No
Update Time = 0.25
Cascaded Loop = No
Engineering Unit Maximum = 1500
Engineering Unit Minimum = 0
Input Range Maximum = 4095
Input Range Minimum = 0
Output Limit High % = 100
Output Limit Low % = 0
PV Alarm High = 0
PV Alarm Low = 0
PV Alarm Deadband = 0
(+) Deviation Alarm = 0
(-) Deviation Alarm = 0
Deviation Alarm Deadband = 0
Status tab
Setpoint = xxx
PID Initialized = no
A/M Station Mode = auto
Software A/M Mode = auto
Status Enable = 0
Proportional Gain = 0.65
Integral Gain = 0.1
Derivative Time = 0
Deadband = 0
Output Bias % = 0
Tieback % = 0
Set Output % =40
Mostly the thing that bothers me is the "max/min scaled input" from the integer block. The description in the help file is kinda vague on that one, not sure if it translates to the "max/min eng. unit" or the "max/min input range"...
Any help would be much appreciated...