Spirax Sarco SP500 - Page 47

IM-P343-35 CTLS Issue 5
47
SP500 Electropneumatic Smart Positioner
9.5.3 CTRLA - direct or reverse control action
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Programming notes
Provides selection of direct (dIRCT) (4 - 20 mA) or reversed (REV) (20 - 4 mA) valve positioning control
action. Press and keys to select desired action. Default action is dIRCT.
Default values for travel limit settings (MIN-T and MAX-T) and early shut-off vent/inflate settings (S-MIN
and S-MAX) will depend on the valve type (2-port or 3-port) and control action (direct or reverse) as follows:
DIR - direct action
Display 2-port 3-port
MIN-T 0% 0%
MAX-T 95% 100%
S-MIN 0.1% 0.1%
S-MAX OFF 0.1%
REV - reverse action
Display 2-port 3-port
MIN-T 0% 0%
MAX-T 95% 100%
S-MIN OFF 0.1%
S-MAX 0.1% 0.1%
Press key to accept the displayed action and advance to minimum travel setting (MIN–T).
Commissioning notes
Selection of direct or reverse action changes the direct of valve plug movement relative to the input
signal. Refer to Figures 63 and 64, and the table shown in Figure 65 for further guidance.
Valve plug position
Valve stem lifting
mA
Increasing input signal
Valve plug position
Valve stem falling
mA
Increasing input signal
Fig. 63
Direct action (DIR)
Fig. 64
Reverse action (REV)