Bronkhorst EL-FLOW Base 2014 - Manual (Page 27)

BRONKHORST HIGH-TECH
4.1.5 Controller Response Adjustment
The controller settling time of EL-FLOW Base instruments is factory adjusted to approximately 1 second
at customer process conditions.
When real process conditions differ from supplied data, or when a faster or slower controller response is
needed, a readjustment can be performed.
Settling time is defined as the time to reach the setpoint (and stay) within ± 2% of the initial setpoint
The picture below shows the basic controller diagram of the EL-FLOW Base. It consists of a standard PID
controller with a number of add-ons.
Basically, when a faster or slower controller response is needed, only the controller gain Kspeed or Kp
has to be changed.
Kp (PIDKp)
Type Access Range FlowDDE FlowBus ModBus PDU
Float RW  0…1E+10 167 114/21 0xF2A8..0xF2A9/62121..62122
Proportional action of the PID controller.
Kspeed
Type Access Range FlowDDE FlowBus ModBus PDU
Float RW  0…1E+10 254 114/1 0xF2F0..0xF2F1/62193..62194
Ti (PIDTi)
Type Access Range FlowDDE FlowBus ModBus PDU
Float RW  0…1E+10 168 114/22 0xF2B0..0xF2B1/62129..62130
Integration action in seconds of the PID controller.
The value should not be changed.
Td (PIDTd)
Type Access Range FlowDDE FlowBus ModBus PDU
Float RW  0…1E+10 169 114/23 0xF2B8..0xF2B9/62137..62138
Differentiation action in seconds of the PID controller.
Default Value: 0.0
This value should not be changed.
∫
d
dt
+
K
speed
S
+
-
Curve
Corr
Sensor
Control Valve
Flow
Setpoint
K
p
K
open
K
normal
K
stable
P
I
D
9.17.061 EL-FLOW Base Series Mass Flow Controllers Page 27