G030
The following is a brief description of the main settings and features of E-BM-AS drivers.
For a detailed descriptions of all available settings, wirings and installation procedures, please refer to the
programming manual E-MAN-BM-AS included in the E-SW-PS Dvd programming software(see section
5
)
6.1 Scale
Scale function allows to set the maximum current supplied to the solenoid, corresponding to the max
valve regulation, at maximum reference signal value.
This regulation allows to adapt the maximum current supplied from the driver to the specific nominal
current of the proportional valves to which the driver is coupled; it is also useful to reduce the maxi-
mum valve regulation in front of maximum reference signal.
For double solenoid valves two different Scale regulations are available : ScaleA for positive referen-
ce signal and ScaleB for negative reference signal
6.2 Bias and Threshold
Proportional valves may be provided with a dead band in the hydraulic regulation corresponding to
their switch-off status.
This dead band discontinuity in the valve’s regulation can be compensated by activating the Bias
function, which adds a fixed preset Bias value to the reference signal (external input or internally
generated).
The Bias function is activated when the reference signal overcome the Threshold value, preset into
the driver.
The Bias setting allows to calibrate the Bias current supplied to the solenoid of the specific propor-
tional valve to which the driver is coupled.
The Threshold setting is useful to avoid undesired valve regulation at zero reference signal when
electric noise is present on the analog input signal: smaller threshold reduces the reference signal
dead band, greater values are less affected by electric noise presence.
If internal reference generation is active (see 6.6), threshold should be set to 0.
For double solenoid valves two different Bias regulations are available: positive reference signal acti-
vates BiasA for solenoid S1 and negative reference signal activates BiasB for solenoid S2
6.3 Ramps
The ramp generator allows to convert sudden change of electronic reference signal into smooth
time-dependent increasing/decreasing of the current supplied to the solenoid.
Different ramp mode can be set:
- single ramp for any reference variation
- two ramps for increasing and for decreasing reference variations
- four ramps for positive/negative signal values and increasing/decreasing reference variations
Ramp generator is useful for application where smooth hydraulic actuation is necessary to avoid
machine vibration and shocks.
If the proportional valve is driven by a closed loop controller, the ramps can lead to unstable beha-
viour, for these applications ramp function can be software disabled (default setting)
6.4 Dither
The dither is an high frequency modulation of the current supplied to the solenoid, to reduce the
hysteresis of the valve’s regulation: a small vibration in the valve’s regulating parts considerably
reduces static friction effects.
Dither frequency can be set in a range from 80 to 500 Hz (default value is 200Hz).
Lower dither setting reduces the hysteresis but also reduces the regulation stability. In some appli-
cation this can lead to vibration and noise: right setting usually depends on system setup.
Default dither is a valid setting for a wide range of hydraulic applications
6.5 Linearization
Linearization function allows to set the relation between the reference input signal and the current
supplied to the solenoid.
Linearization is useful for applications where it is required to linearize the valve’s regulation in a defi-
ned working condition (e.g. maximum pressure control at defined working flow)
6.6 Internal Reference Generation
Internal generation of reference values is software selectable.
In this mode the 4 digital inputs of the driver (DI1..DI4) allow to activate the desired internal referen-
ce signal, among the different driver’s stored values: external control unit can thus manage complex
machine profile by simple switching the reference signal, by 4 digital inputs (see 4.7).
The digital inputs are software configurable into 2 different reference selection mode:
• Standard mode
each digital input corresponds to a different value; up to 4 different internal values are available
(2+2 with E-BM-AS-PS-05H driving two single solenoid valves)
• Binary mode
each digital input combination corresponds to a different value; up to 15 different internal values
are available (3+3 with E-BM-AS-PS-05H when driving two single solenoid valves)
A dedicated ramp time value can be set by software for each available stored reference value.
Note: with all input signals (DI) set to zero, the driver can be commanded by external analog refe-
rence also if internal reference generation is selected (for more information please refer to the pro-
gramming manual E-MAN-BM-AS).
6.7 Hydraulic Power Limitation (/W option, only for drivers E-BM-AS-PS-05H)
E-BM-AS drivers with /W option electronically perform hydraulic power limitation on:
- direct and pilot operated flow control valves
- direct and pilot operated directional control valves + mechanical pressure compensator
- variable displacement pumps with proportional flow regulator (e.g. PVPC-*-LQZ, tech.tab. A170 )
The driver receives the flow reference signal by the analog external input CMD1 (see 4.2) or by the
internal generator (see 6.6), and a pressure transducer, installed in the hydraulic system, has to be
connected to the driver’s analog input CMD2.
When the actual requested hydraulic power pxQ (CMD2xCMD1) reaches the max power limit
(p1xQ1), internally set by software, the driver automatically reduces the flow regulation of the valve.
The higher is the pressure feedback the lower is the valve’s regulated flow:
Flow regulation = Min
(
PowerLimit [sw setting]
; Flow Reference [CMD1]
)
Transducer Pressure [CMD2]
6
MAIN SOFTWARE PARAMETER SETTINGS
t
t
reference
current
reference
Scale B
Scale A
current
reference
Bias B
Bias A
Bias A
Scale A
t
t
t
DI4
DI3
DI2
DI1
t
reference
reference
Q
Q
1
p1
p
pressure
feedback
reference signal
for valve regulation
Bias B
Scale B
Solenoid S1
regulation
Solenoid S2
regulation
Bias A
Bias B
Threshold
current
current
Solenoid S1
Solenoid S2
6.1, 6.2 - Scale, Bias & Threshold
6.3 - Ramps
6.5 - Linearization
6.4 - Dither
6.6 - Internal Reference Generation
6.7 - Hydraulic Power Limitation
Regulation curve with and
without power limitation.
p1 x Q1 = max power limit
Single internal generator selection (standard mode)
DI1 DI2 DI3 DI4 Reference
OFF
OFF OFF OFF External
ON OFF OFF OFF Generation 1
(*) ON OFF OFF Generation 2
(*) (*) ON OFF Generation 3
(*) (*) (*) ON Generation 4
Double internal generator selection (standard mode)
DI1 DI2 S1 DI3 DI4 S2
OFF
OFF External OFF OFF External
ON OFF Generation 1 ON OFF Generation 1
(*) ON Generation 2 (*) ON Generation 2
(*) Note: Don’t care
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