Parker RAC Europe
PSD04 | User manual ver. 3.6 | Code 144PSDI364
Page 20 of 74
The Driver type (parameter DrTy) used depends on the hardware, while the Stepper type (parameter StTy) depends
on the motor to be controlled; currently, the PSD04 can only be used with Parker Sporlan bipolar stepper motors.
The driving mode can be selected through parameter Driving mode selection (Pi01).
The Valve duty cycle (parameter Pr45) represent the limit of continuous operating of the valve: limiting the continuous
activity of the valve reduces the heating of same.
For example: setting Pr45 = 70% means for every 70 ms in which operational current is used, there will be 30 ms in
which maintenance current will be applied on the valve.
If the parameter is set to 100%, this algorithm is deactivated.
Furthermore, this procedure applies only to the normal operation of the valve: all forced movements (for example
synchronisation closure, positioning caused by probe errors or communication errors) are continuous until the target
position is reached.
The valve is automatically resynchronized at every switch on.
During the resynchronization the valve is completely closed; the resynchronization is necessary to realign the physical
position of the complete closure with the 0 step position.
In debug mode the speed follows the debug step rate; in manual mode the speed follows the maximum speed.
During normal operation of the valve, it assumes the 0% position corresponds to the physical position defined by
Minimum regulation steps, and that the 100% position corresponds to the physical position defined by Maximum
regulation steps.
A resynchronization request can be signalled using various methods:
-
rising edge on digital input DI2 (if DI2 is configured as “resynchronization command” and Enabling mode
(parameter Pr06) is configured as “standalone”
-
rising edge on Resynchro request (ResR) if Enabling mode (parameter Pr06) is configured as “network”
-
internal request from the algorithm
-
upon reaching the maximum limit of operational hours (Working hours, parameter Pr40), Resynchronization
interval (parameter Pr41), if configured.
A resynchronization request is performed only when it is safe to do, so when the state is Stand-by: this means that a
resynchronization request made when the valve is enabled is performed automatically only when it is disabled.
It is not currently possible to cancel a request.
The valve moves with a maximum velocity defined by the Stepping rate parameter.
The positioning speed depends on the operation mode:
-
during resynchronization phase the maximum speed is applied, but at the end of the positioning the speed
follows a deceleration ramp
-
in debug mode is used the speed of the Debug step rate (parameter Prd0)
-
in manual mode and for all other positioning is used the maximum speed.
Using Limit valve opening (parameter Pr30) it is possible to adapt the valve to the application.
For example, for a valve with a maximum rating of 10 kW fitted to a machine with 7.5 kW, Pr30 would be set to 75%.
So, if the request position target is 90%, the final real position of the valve may be 67.5% = 90 x 75% of the
Maximum regulation steps.
The displayable variables for the current position and set-point in % are all referenced to the actual range of use of the
valve (0 - Pr30%), while the position in steps is the real position.
