MTS Series 298 Hydraulic Service Manifold - Manual (Page 18)

Series 298 Hydraulic Service Manifold 18
Functional Description
Introduction
Proportional valve
The Model 298.12 Actuator Manifold can produce a low output pressure, ramp to
and from high operating pressure, and it can perform a rapid shutoff function.
Some controllers require the Model 413.07 Service Manifold Interface to provide
the necessary control for the proportional valve. The proportional valve controls
a high pressure poppet which applies the hydraulic pressure to the servovalve
ports. However, high pressure is always available at the pilot pressure port (for
servovalves that support pilot pressure).
Low pressure mode
The low output pressure is adjustable from 0.8 to 10.3 MPa (116 to 1500 psi),
which corresponds with the adjustable current from 130 mA to 340 mA to the
proportional valve. This limits the force of the actuator without lowering the
hydraulic power unit output pressure. The maximum flow rate is 18.9 L/min (5
gpm).
Ramp to high pressure
The ramp from low pressure to high pressure can be adjusted from 2 to 5
seconds. The ramp also applies to the high to low pressure transition. The ramp
allows systems to slowly apply hydraulic pressure to the test specimen or
assembly. This prevents damage to the test specimen by eliminating any sudden
bumps (or unexpected actuator movement) when hydraulic pressure is supplied
to the actuator.
Rapid shutoff
The rapid shutoff allows hydraulic pressure to be quickly removed from the
actuator manifold without causing turbulence in the hydraulic lines.
550 ms
50 ms
Low High Low Off
Rapid
Shutdown
Hydraulic Control Switches
2-5 Second Ramp
21 MPa
(3000 psi)
10 MPa
(1500 psi)
1 MPa
(120 psi)
Low Pressure
Adjustment Range