Burkert Type 8611 - Manual (Page 57)

57
FunctionsoftheConfigurationLevel
12.3.6. 3P – T -
Quasi-continuous 3-state control with open/closed valves
or motor valve
This function can be used to implement quasi-continuous controls using open/closed valves or motor valves.
Here, unlike in purely open/closed controls that only provide for the states open or closed, the control time for the
opening or closing is varied proportionally to the set-point/actual value deviation. The valves are controlled via 2
transistor outputs of the controller.
P
8611
4 - 20 mA
Control of valve 1
Operating principle
NC = closed with no current
Control of valve 2
Operating principle
NO = open with no current
Set-point value
Actual value
p
r
p
tank
VLV1
(NC)
VLV2
(NO)
Controller setting:
MODE = P, 3P – T, NC, TMN1, NO, TMN2, NORM
Figure 41: Example of a three-state pressure control
Controller setting:
MODE = T, 3P – T, NC, TMN1, NC, TMN2, NORM
T
8611
4 - 20 mA
VLV1 VLV2
M
Figure 42: Example of a three-state temperature control
english
Type 8611