Technical information

IM-P343-29 CH Issue 5 45
Fig. 42
Provides access to more advanced valve tuning functions including:
- Dead-band (valve positioning sensitivity) (dBANd)
- Shut-off minimum (ensures tight closure) (S-MIN)
- Shut-off maximum (ensures tight closure) (S-MAX)
- Characterisation (signal / lift relationship) (CHAR)
- Time open (slows down valve opening) (T-UP)
- Time close (slows down valve closure) (T-dWN)
- Travel switch 1 normally open (sets software travel switch) (TS1)
- Travel switch 2 normally closed (sets software travel switch) (TS2)
Programming notes
Press key to advance to deadband (dBANd). Repeated pressing of key
will scroll round all TUNE functions. If you do not wish to alter TUNE default
values press key to advance to RUN in the main menu.
Commissioning notes
Each TUNE function has a default value as listed in the Installation and Maintenance
Instructions. Default values are based on a 2-port normally closed valve having maximum
95% lift and an input signal span range 4 - 20 mA.
TUNE values should be adjusted to suit the valve type and application. Functions include:
1. The facility to alter deadband positioning sensitivity (to dampen out signal fluctuations).
2. Setting input signal to achieve tight shut-off (inflation and deflation of actuator).
3. Relationship between valve lift to input signal.
4. Slowing down the valve open or closing time duration.
5. Setting the switching position for the software travel switches.
More detailed information is provided for each TUNE function.
9.6 TUNE - setting of valve tune functions
Dead-band
(dBand)
Shut-off maximum
(S-MAX)
Characterisation
(LIN / FAST /
EQUAL)
Time to open
(T-UP)
Time to close
(T-dWN)
Travel switch 2
(TS2)
Normally closed
Travel switch 1
(TS1)
Normally open
Shut-off minimum
(S-MIN)
TUNE