3725 Electropneumatic Positioner is mounted on pneumatic control valves and is used to assign the valve position (controlled variable x) to the control signal (reference variable w). The positioner compares the electric control signal of a control system to the travel or opening angle of the control valve and issues a signal pressure (output variable y) for the pneumatic actuator.
Operation A user-friendly, intuitive concept using three capacitive keys and an LCD has been developed: users select parameters by
touching the arrow keys and confirm the settings with the confirmation key. In the menu, all parameters are listed in one level,
meaning there is no need to search through submenus. All parameter settings can be read and changed on site. The menu is ices in hazardous areas.
Electropneumatic positioner
Housing of polyphthalamide
Attachment to linear actuators according to IEC 60534-6 or SAMSON integral attachment
Attachment to rotary actuators according to VDI/VDE 3845
Attachment to double-acting actuators with Type 3710 Reversing Amplifier
Easy operation with intuitive navigation menu using three capacitive keys
Easy-to-read display in any mounting position thanks to rotatable reading direction
Variable automatic start-up
Preset parameters
All parameters saved in non-volatile EEPROM
Tight-closing function can be activated
Automatic zero monitoring
Non-contact position sensing
Unaffected by environmental effects and steam hammering
Type 3725 Positioner | ||
Travel, adjustable | Direct attachment to Type 3277 Actuator: 3.75 to 30 mm Attachment acc. to IEC 60 534-6-1 (NAMUR): 3.75 to 50 mm Attachment to Type 3372 Actuator: 15/30 mm Attachment to rotary actuators: 24 to 100° | |
Reference variable w | Signal range | 4 to 20 mA · Two-wire device with reverse polarity protection |
Split range operation | 4 to 11.9 mA and 12.1 to 20 mA | |
Static destruction limit | ±33 V | |
Minimum current | 3.8 mA | |
Load impedance | Š 6 V (corresponds to 300 fi at 20 mA) | |
Supply air | Supply pressure | 1.4 to 7 bar (20 to 105 psi) |
Air quality acc. to ISO 8573-1 (2001) | Max. particle size and density: Class 4 · Oil content: Class 3 Pressure dew point: Class 3 or at least 10 K below the lowest ambient temperature to be expected | |
Signal pressure (output) | 0 bar up to the capacity of the supply pressure · Can be limited to approx. 2.4 bar by software | |
Characteristics | 3 characteristics for globe valves · 9 characteristics for rotary valves | |
Hysteresis | Š 0.3 % | |
Sensitivity | Š 0.1 % | |
Transit time | < 0.5 s not permissible for initialization, adaptation using volume restriction | |
Direction of action | w/x reversible | |
Air consumption | Š 100 ln/h with a supply pressure up to 6 bar and a signal pressure of 0.6 bar | |
Air output capacity | Actuator pressurized | At Op = 6 bar: 8.5 mn⊃3;/h · At Op = 1.4 bar: 3.0 mn⊃3;/h · KVmax (20 °C) = 0.09 |
Actuator vented | At Op = 6 bar: 14.0 mn⊃3;/h · At Op = 1.4 bar: 4.5 mn⊃3;/h · KVmax (20 °C) = 0.15 | |
Permissible ambient temperature | –25 to +80 °C Limits in test certificates additionally apply for explosion-protected devices. | |
Influences | Temperature | Š 0.15 %/10 K |
Supply air | None | |
Vibrations | Š 0.25 % up to 2000 Hz and 4 g according to IEC 770 | |
Electromagnetic compatibility | Complying with the requirements of EN 61000-6-2, EN 61000-6-3, EN 61326-1 and NAMUR Recommendation NE 21 | |
Electrical connections | One M20x1.5 cable gland for 6 to 12 mm clamping range Cage clamp terminals for 0.2 to 1.5 mm⊃2; wire cross-sections | |
Explosion protection | II 2 G Ex ia IIC T4 | |
Degree of protection | IP 66 |
-Manuals
Samson 3725 Electropneumatic Positioner
-Data sheet