ABB CM30 - Loop 1 (2) Mot Valve

ControlMaster CM30 and CM50
Universal process controllers,
1
/4 and
1
/2 DIN 6 Basic Level
IM/CM/ED–EN Rev. B 21
…Basic
Loop 1 (2) Mot Valve
Motorized Valve Output With Feedback
Motorized Valve Output Without Feedback (Boundless)
A motorized valve output without feedback (boundless) process controller provides an output that is effectively the
time derivative of the required regulator position (the controller signals the regulator, not where to go to [position
derivative], but in the direction to travel and how far to move) by a series of integral action pulses. Therefore, the
controller does not need to know the absolute regulator position and is not affected when the regulator reaches the
upper or lower limit, as determined by the regulator’s limit switches (hence the term ‘boundless’).
When a deviation from setpoint is introduced, the regulator is driven for a length of time equivalent to the proportional
step. The regulator is then driven by integral action pulses until the deviation is within the deadband setting.

PV
SPT
(OP x Ratio) + Bias
PID
Motorized
Valve
Controller
Open Relay
Close Relay
Position Feedback
+

Control
Deviation
Proportional
Step
Raise
Lower
Integral Action Pulses 
Proportional
Step
Integral Action
Pulses
Time 
Time 