Bronkhorst®
Instruction Manual mini CORI-FLOW ML120
9.17.097G
57
The following digital parameters are involved in optimizing proportional control:
Name
Process/
Parameter
Modbus
register no
Value
Purpose/Remarks
Valve Open (190)
114/24
62145…
62146
as required set minimum current/voltage required to open the valve
Setpoint Slope (10)
1/2
35
0
adjustment time when changing setpoint from 0% to 100% (range
corresponds with 0…3000 seconds)
PID-Kp (167)
114/21
62121…
62122
10
controller proportional action
(increase to speed up controller, decrease to slow down)
PID-Ti (168)
114/22
62129…
62130
0.1
controller integral action
(decrease to speed up controller, increase to slow down)
PID-Td (169)
114/23
62137…
62138
0
controller derivative action (prevents setpoint overshoot)
For more information about the PID controller, see
Digital parameters - Controller
in this manual or the FlowPlot manual
(document 9.17.030).
5.3.6
On/off control settings
Minimizing valve temperature
When working with fluids with a low boiling/evaporation point, it can be useful to limit the power dissipation by a shut-off
valve, in order to minimize the temperature rise caused by valve actuation. A shut-off valve needs a stronger signal to open
it than to keep it open (hold signal). Once it is open, the signal can safely be set to a lower point, reducing power
dissipation by the valve coil (thereby minimizing temperature rise).
On/off control without hold signal
On/off control with hold signal