EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
Telephone: (231) 929-1660
Oilgear
Fax:
(231) 929-7879
1424 International Dr
Issued May 31, 2018
Web Site:
www.oilgear.com
Traverse City, MI USA 4 9 6 8 6
Bulletin 836260F
23
Pressure Feedback Source
: The Pressure Feedback Source selects the source of the pressure
feedback for the program. Valid entries are (1) Analog Input 1, (2) Analog Input 2, (3) Analog
Input 3, (4) LVDT 1 (Analog Input 4), or (5) Ramp 1.
Program Output Destination
: The Program Output Destination selects the output of the program.
Valid entries are (0) Pump Controller or (1) Direct. If the Pump Controller is chosen, the output of the
Program will be the input to the Pump Controller module. If Direct is chosen, the output of the Program
will by-pass the Pump Controller module and is passed directly to the servo driver. Under most
circumstances, the Pump Controller should be chosen as the output destination.
KP
: KP provides the proportional gain setting to control the pressure limit slope. KP is configured as
a percentage, with 0% to no integral gain and 100% equivalent to maximum proportional gain.
KI
: KI provides the integral gain setting to PI control loop of the program. KI is configured as a
percentage, with 0% to no proportional gain and 100% equivalent to maximum integral gain.
Q to P Control Switch Preset:
The Q to P Control Switch Preset allows for direct numeric input. The
preset has a slightly different characteristics depending on the value of Q to P Control Switch Source
entry.
If the Q to P Control Switch Source is set to
0 (Preset Value)
, the preset is configured as a
percentage, with 0% equivalent to a 0VDC input signal and 100% equivalent to a +10VDC signal.
This value is used as the toggle point between Pressure and Flow control.
If the Q to P Control Switch Source is set to
6 (Limit Offset)
, the Preset is configured as a
percentage, with 0% equivalent to a 0VDC input signal and 100% equivalent to a -10VDC offset
signal. The offset value is added to the Pressure Command Source signal to make the Toggle Point
between Pressure and Flow control.
Finally, if the Q to P Control Switch Source is set to
7 (Limit Attenuation)
, the Preset is
configured as a percentage, and the Control Switch Toggle Point will be equal to the percentage of
the Pressure Command signal.
Q to P Control Switch Source:
The Q to P Control Switch Source selects the source of the Flow
to Pressure Toggle Point command. Valid entries are (1) Analog Input 1, (2) Analog Input 2, (3)
Analog Input 3, (4) LVDT 1 (Analog Input 4), (5) Ramp 1, (6) Limit Offset or (7) Limit Attenuation.
Program Overview
: The Pressure with Flow Preset Control Program functions as either Flow
Control or Pressure Control, depending on whether the feedback pressure is greater or less than the Q
to P Control Switch signal.
Under most circumstances, the control begins as a Flow Control. The algorithm will switch from a
Flow Control to Pressure Control once the feedback pressure signal is greater than the Q to P Control
Switch command. Once in Pressure Control, the Pressure command is compared to the feedback
value to produce an error value. The error is multiplied by the KP and KI constants to produce the
Yp and Yi contributions of the program output. In the pressure mode, the Flow command acts as a
limit to the pressure control loop.
If using EPC software version 1.06 or earlier, see Appendix A for Generation 1 control.
