Spirax Sarco SP400 - VALVE - valve type; CTRLA - direct or reverse control action

IM-P343-37 CTLS Issue 4
36
start of text under grey section header box
start of text continuing from previous page
TRANSLATION RUN OVER
SP400 Electropneumatic Smart Positioner
9.5.1 VALVE - valve type
•
Programming notes
2-port
On 2-port valves when the setpoint is 100%, the positioner will open to 95% of the stroke and display 100%,
to prevent the back of the plug hitting the bonnet. Tight shut-off is set to 1% on 'vent' operation.
3-port
On 3-port valves tight shut-off is set to 1% on 'vent' and 'fill' operations to ensure shut-off on both seats.
When setpoint is 100%, the positioner will open to 100% of the stroke and display 100%.
Use the and keys to select type. Press the key to accept displayed type and advance to
control action (CTRLA).
9.5.2 CTRLA - direct or reverse control action
•
Programming notes
Provides selection of direct (dIRCT) (4 - 20 mA) or reversed (REV) (20 - 4 mA) valve positioning control
action. Press the and keys to select desired action. Default action is dIRCT.
Press the key to accept the displayed action and advance to deadband (DBAND).
Commissioning notes
Selection of direct or reverse action changes the direct of valve plug movement relative to the input
signal. Refer to Figures 40 and 41 for further guidance.
Valve plug position
Valve stem lifting
mA
Increasing input signal
Valve plug position
Valve stem falling
mA
Increasing input signal
Fig. 40
Direct action (DIR)
Fig. 41
Reverse action (REV)