BRONKHORST ES-FLOW 1 C Series Instruction Manual page 34

The algorithm is based upon the difference between the setpoint and the measured value (called the error value). The
correction signal to eliminate the error is assembled from 3 components (giving the algorithm its name):
·
The P-action (proportional) multiplies the error value by a constant factor, to adjust the measure towards the (new)
setpoint.
·
The I-action (integral) amplifies the correction signal with a factor depending on the integral of the error value over time.
·
The D-action (derivative) reduces the strength of the P-action, to prevent overshoot when the (new) setpoint is reached.
The proportional action is enhanced by one of three additional response factors, depending on the control cycle stage:
·
Open from zero: the setpoint is larger than zero and the measured value is below 2% of the full scale range.
·
Normal step: the measured value differs more than 2% from the setpoint, typically after changing the setpoint (step).
·
Stable situation: the measured value differs less than 2% from the setpoint.
Control characteristics are optimized during production. These parameters should only be changed if absolutely necessary,
and only by or under the supervision of trained service personnel.
Controller Speed
Type
Float
This parameter sets the overall controller speed factor for the selected fluid. Controller speed is set ex factory between value
'0.5' (slow) and '2' (fast). The default value is '1'.
PID-Kp
Type
Float
PID controller proportional action, multiplication factor.
PID-Ti
Type
Float
PID controller integral action in seconds.
PID-Td
Type
Float
PID controller derivative action in seconds. The default value is 0.0.
Open From Zero Response
Type
Unsigned char
Response factor, applied to proportional action when opening the valve from 0%.
·
Default value: 128 (no correction)
·
Other values adjust the controller gain (correction signal) as follows: Controller gain = Controller Speed * PID-Kp *
(response factor - 128)
1.05
34
Access Range
RW 0.2...5
Access Range
B
RW 0...1E+10
Access Range
B
RW 0...1E+10
Access Range
B
RW 0...1E+10
Access Range
B
RW 0...255
Instruction Manual ES-FLOW™ 1xxC
Bronkhorst®
FlowDDE FLOW-BUS
254 114/30
FlowDDE FLOW-BUS
167 114/21
FlowDDE FLOW-BUS
168 114/22
FlowDDE FLOW-BUS
169 114/23
FlowDDE FLOW-BUS
165 114/18
Modbus
0xF2F0...0xF2F1/62193...62194
Modbus
0xF2A8...0xF2A9/62121...62122
Modbus
0xF2B0...0xF2B1/62129...62130
Modbus
0xF2B8...0xF2B9/62137...62138
Modbus
0x0E52/3667
9.17.153E