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Pressure and flow control system SYDFE1 series 2X, 3X
| Commissioning
Bosch Rexroth AG, Edition 10.2021, RE 30011-B
controlling when the maximum pressure value is provided as command value (+10
V), but the final value of the pressure transducer’s measuring range.
Two options are provided for adjustment:
• Pressure command value adjustment
• Actual pressure value adjustment
With pressure command value adjustment, the pressure command value is
normalized to the measuring range of the pressure transducer and fed forward
accordingly.
With this method, no adjustments need to be made on control electronics
VT 5041-3X.
Example:
Measuring range of standard
pressure transducer:
0... 315 bar
Selected operating pressure:
250 bar
The following is valid for the pressure command value provision: 10 V/315 bar =
31.7 mV/bar (= factor)
250 bar x 31.7 mV/bar = 7.94 V
i.e. the pressure command value is normalized to the factor of 31.7 mV/bar;
in order to provide the operating pressure as pressure command value, a pressure
command value of 7.94 V has to be generated.
General formula:
Factor:
10 V/measuring range of PT (Pressure transducer)
Pressure command value [bar]: Pressure x factor = pressure command value [V]
In the case of actual pressure value adjustment, the actual pressure value is
normalized to the operating pressure.
With the factory setting, the control electronics VT 5041-3X.. converts the signal of
the pressure transducer internally into the range of 0...+10 V.
To change the signal range (= gain) of the actual pressure value, use potentiometer
R2 (front panel) of control electronics VT 5041-3X.
Proceeding while the system is running:
1.
Close all directional valves. No oil flow permitted!
2.
Provide a swivel angle command value of >+5 V (test jack 3 = +5 V)
3.
Set the pressure command value to 5 V (= half operating pressure)
4.
Then turn potentiometer R2 until the pressure gauge that measures the pump
pressure indicates half the operating pressure.
– For checking purposes: The provision of a command value of +10 V must
result in the full operating pressure (± 3 bar).
8.1.10 Pressure control
The oil volume between the consumer and the pump has a decisive influence on
the control dynamics of the pressure control loop. Switches S3.1 to S3.3 can be
used to adjust the controller to the connected oil volume; whereas when switching
input “Switch Td“ (22c) is activated, switches S3.4 to S3.6 become active.
With the factory setting, switches S3.1 to 3.6 are in the OFF position
Pressure command value
adjustment
Actual pressure value
adjustment
Adjustment to the
connected oil volume
