The proven type 3000 electro-pneumatic pressure control devices from Marsh Bellofram have been re-engineered to provide separate models for general industrial use and for test benchesThe proven type 3000 electro-pneumatic pressure control devices from Marsh Bellofram have been re-engineered to provide two levels of performance for operations associated with a wide range of manufacturing, production and research processes. One model in the range, the type 3200, is designed to cover general engineering applications where varying electrical control signals can be used to generate proportional output pressures. These are normally pneumatic but can also be other gases or even indirect hydraulics.
For more sophisticated requirements, the digital model type 3500 is typically suitable for use with test benches in the medical and aerospace industries.
This is a micro processor controlled device which provides an unparalleled level of accuracy of 0.1%.
All products feature twin solenoid valves with internal pressure sensors providing closed loop accuracy.
Minimal air consumption is achieved, with no constant bleed at steady state pressures and various models are available covering output pressures from vacuum to 1,000 psig.
They can be used as stand alone units for many applications with a flow of 1.2 SCFM at 100 psi.
Integrated or separate flow booster relays are also available to achieve flow rates of up to 2000 SCFM if required.
Both versions are also available with double control loops, which can be used to correct external system inaccuracy, such as pipe losses.
The compact housings are weatherproofed and the controllers operate within a temperature range of 0ø to +60øC and can be mounted in any orientation, whichever is most convenient for an individual application.
Manifold or din RAIL mounted controllers can also be supplied for panel mounted assemblies.
Both the 3200 and 3500 models operate on supply voltages from 15 - 24 Vdc with supply currents of 80mA standby, up to 325mA maximum.
On the type 3200 command signals are either are 0 - 10 Vdc or 4 - 20mA, 0-10Vdc monitor feedback is available as standard.
The type 3500 features digital control using self tuning Proportional -Integral-Derivative (PID), which can be manually adjusted if required.
Digital communications via PLC or PC can be used for programming.
Control can be either digital or analogue, or alternatively there is an optional local keypad/display for programming.
Command and monitor signals are selectable from a menu, including analogue, digital and PWM (pulse with modulation) or can be modified via the software.
PC programming is through MS Windows based software, which is provided free with the package, and communication is via RS485 on which up to 8 devices can also be controlled on a single line.
Plans for the future include fieldbus communications such as Profibus and Devicenet.