OilGear EPC 300 Series User manual

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
Telephone: [phone] Oilgear
Fax: [phone] International Dr Issued May 31, 2018
Web Site: www.oilgear.com Traverse City, MI USA 49686 Bulletin836260F
1
EPC
300 Series (-3xx)
User Manual

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
Telephone: [phone] Oilgear
Fax: [phone] International Dr Issued May 31, 2018
Web Site: www.oilgear.com Traverse City, MI USA 49686 Bulletin836260F
2
Table of Contents
1 Introduction............................................................................................................................................ 4
2 Basic System Overview........................................................................................................................ 4
3 General Instructions .............................................................................................................................. 5
3.1 Password Protection........................................................................................................................5
3.2 PC Interface Groupings.................................................................................................................. 5
4 Module Configuration........................................................................................................................... 6
4.1 General Configuration .................................................................................................................... 6
4.1.1 Password Protection (000) ....................................................................................................6
4.1.2 Operating Modes (200) .........................................................................................................6
4.1.2.1 Dynamic Function Selection with Fault Monitor ..........................................................7
4.1.2.2 Dynamic Function Selection with Watchdog Monitor ..................................................7
4.1.2.3 Static Function Selection with Watchdog Daisy Chain ................................................7
4.1.2.4 Dynamic Function Selection with Limit Monitor ..........................................................8
4.1.2.5 Static Function Selection with Fault Monitor................................................................ 8
4.1.2.6 Static Function Selection with Watchdog Monitor ....................................................... 8
4.1.2.7 Static Function Selection with Watchdog Daisy Chain ................................................ 9
4.1.2.8 Static Function Selection with Limit Monitor .............................................................. 9
4.1.3 Program Block Configuration (21x).......................................................................................10
4.1.4 EPC Hardware and Software Information............................................................................11
4.1.5 USB Communication .............................................................................................................12
4.1.6 Update Rate...........................................................................................................................12
4.2 Program Configuration ....................................................................................................................12
4.2.1 Overview ...............................................................................................................................12
4.2.2 PIControl Algorithms ............................................................................................................12
4.2.3 Pressure Control Programs (40x, 41x) ..................................................................................13
4.2.4 Flow with Pressure Limit Programs - Generation 2 (42x, 43x).............................................15
4.2.5 Load Sense Control Programs (44x, 45x)..............................................................................18
4.2.6 Simple Flow Control Programs (46x, 47x).............................................................................21
4.2.7 Pressure Control with Flow Preset Programs - Generation 2 (48x, 49x)..............................22
4.2.8 Advanced Control with Feed-Forward Programs - (50x, 51x)..............................................26
4.3 Pump Controller Configuration .......................................................................................................30
4.3.1 Overview ...............................................................................................................................30
4.3.2Configuration ........................................................................................................................30
4.3.2.1 Function Zero Stroke Command ..................................................................................31
4.3.2.2 Stroke Controller ..........................................................................................................31
4.3.2.3 HP Limiter ...................................................................................................................32
4.3.2.4 Output Polarity .............................................................................................................32
4.3.2.5 Output Current Limit ....................................................................................................33
4.3.2.6 Dither ...........................................................................................................................33

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
Telephone: [phone] Oilgear
Fax: [phone] International Dr Issued May 31, 2018
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3
4.3.3 Configuration Example ..........................................................................................................34
4.4 Analog IO Configuration .................................................................................................................35
4.4.1 General Purpose Analog Input Configuration ........................................................................35
4.4.2 LVDT Fine-Adjustable Analog Input Configuration..............................................................38
4.4.3 Programmable Analog Outputs .............................................................................................39
4.4.4 Servo Valve Driver with Stroke Feedback ............................................................................40
4.4.4.1 Servo Attenuation and Offset ......................................................................................40
4.4.4.2 Stroke Feedback Device ..............................................................................................41
4.4.4.3 Adjustment Mode .........................................................................................................41
4.4.5 LVDT Adjustment Algorithm ................................................................................................43
4.4.5.1. Determining LVDT Configuration Range ...................................................................43
4.4.5.2 Adjustment Algorithm ..................................................................................................44
4.5 Advanced Configuration..................................................................................................................46
4.5.1 Horsepower Limit Factor Calculation....................................................................................46
4.5.1.1 Experimental HP Limit Factor .....................................................................................47
4.5.1.2 Theoretical HP Limit Factor ........................................................................................48
4.5.2 Ramp Configuration ...............................................................................................................50
5 Module Diagnostics ............................................................................................................................. 53
5.1 Diagnostic Representation of Numbers ..........................................................................................53
5.1.1 DAC Counts ..........................................................................................................................53
5.1.2 Voltage and Percentages .......................................................................................................53
5.2 Basic Diagnostics on Front Panel ...................................................................................................53
5.2.1 Run / Fault LED ....................................................................................................................54
5.2.2 Valve Current LED................................................................................................................54
5.2.3 Feedback LED ......................................................................................................................54
5.2.4Testpoint.................................................................................................................................54
5.3 Basic Diagnostics with PC Interface ..............................................................................................55
5.4 Programmable Outputs Diagnostic .................................................................................................56
5.5 Advanced Diagnostics.....................................................................................................................56
5.5.1 Module Faults ........................................................................................................................56
5.5.2 System Messages ..................................................................................................................57
6 Technical Data....................................................................................................................................... 58
6.1 Module Pinout .................................................................................................................................58
6.3 Specifications ..................................................................................................................................59
6.4 IO Summary ....................................................................................................................................59
6.5 Cable Recommendations and Terminal Information .......................................................................59
7 Technical Support ................................................................................................................................. 60
8 Ordering Information........................................................................................................................... 61

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
Telephone: [phone] Oilgear
Fax: [phone] International Dr Issued May 31, 2018
Web Site: www.oilgear.com Traverse City, MI USA 49686 Bulletin836260F
1Introduction
The EPC is a fully programmable microcontroller-operated controller and
amplifier for servo controlled hydraulic pumps and valves. The unit can be
configured for several types of control applications including:
•FlowControl
•Pressure Control or Load Control
•FlowControl withPressure Limit(PQ-Control)
•Horsepower Control (Pump Stroke and Pressure)
•Pressure Control with Flow Preset
•Advanced Control with Feed-Forward.
2 Basic System Overview
The EPC allows one (1) single control axis with a power amplifier to drive VS-, VV- and VM-controlled
pumps and valves. The basic pump controller configuration allows for closed loop response with both
stroke position and pressure feedback. In addition, two (2) independent function programs can be
dynamically selected with adigital input signal. The unit provides a digital outputfor simple diagnostics or a
watchdogsignal.
Three(3)general-purposeanaloginputsare provided forcommandandpressurefeedbacksignalsincluding
±10 VDC, 0-to-20 mA, or 4-to-20 mA (see Section 6.4 Note 3 for current mode resistor). Additionally, one
(1) analog input is provided as a dedicated fine-adjustable LVDT stroke feedback device. The module allows
for(2) two low-power programmable output signals.
The device is configured by first assigning one of twelve (12) built-in function programs to each of the two
(2) program blocks. Typically, the output of the function programs is then passed to the Pump Controller,
which providesthe valve command.
Figure 2: System Overview
Figure 1: EPC
Module
4
Analog
Outputs
Analog
Inputs
Stroke Feedback
Pressure Feedback
Pump
Controller
Block
Selection
Digital
Output
Diagnostics
Program Block 2
(Program 0..12)
Program Block 1
(Program 0..12)
Digital
Input

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
Telephone: [phone] Oilgear
Fax: [phone] International Dr Issued May 31, 2018
Web Site: www.oilgear.com Traverse City, MI USA 49686 Bulletin836260F
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If the full features of the module are used, up to three (3) independent closed loop PI (Proportional with
Integral) control algorithms are utilized. Most function programs provide a closed loop control algorithm for
pressure or stroke, while the Pump Controller can be configured for both stroke and power feedback.
The module is programmable through the PC Interface software. Various Forms in the software will be
discussed throughout the manual. Programming items are located in these Forms.
3 General Instructions
3.1 Password Protection
The EPC allows for edit protection of all programmable parameters. Please refer to Section 4.1.1 for a
thorough discussion of Password Protection.
3.2 PC Interface Groupings
The PC interface provides a programming and monitoring interface. A toolbar menu loosely groups
functions into Forms in the following manner:
File File, Print, and Communication Commands
General Password and Communication Setup,
Program Selection and Mode Selection
(program items 000 and 2xx)
Program Program Configuration (program items 4xx and 5xx)
Pump Controller Pump Controller Configuration
(Program items 8xx)
Diagnostics General Purpose Input Configuration,
Analog IO Configuration Fine-Adjustable Input Configuration (LVDT),
Diagnostics, Servo Driver Configuration,
Programmable Output Selections
(Program items 84x, 85x, 86x, 88x, and 93x)
Diagnostics Ramp Configuration and Advanced HP Limit Setup
Advanced Configuration (program items 87x and 810)
Language Select English, German or Italian
Help User Help
Items are programmable either through Numeric Input boxes or Drop-Down List boxes.

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
Telephone: [phone] Oilgear
Fax: [phone] International Dr Issued May 31, 2018
Web Site: www.oilgear.com Traverse City, MI USA 49686 Bulletin836260F
4ModuleConfiguration
4.1GeneralConfiguration
General Configuration parameters include Password, Mode, and Communication Setup Parameters.
4.1.1Password Protection (000)
ProgramItem Range Description
000 0 to 255 Password Table 1: Password Protection
The EPC has a simple lockout password that can be used to protect the program configuration from
accidental changes. The password is entered through program item 000 in the General Configuration
Form.
If the password is set to 249, the user will be able to modify any editable entry. Any other password
will place the device in read-only mode. The user will not be able to modify any entry in this mode.
4.1.2 Operating Modes (200)
ProgramItem Range Description
200 0 to 7 Operating Mode:
0: DynamicFunctionSelectionwithFaultMonitor
1: Dynamic FunctionSelection with Watchdog Monitor
2: Static Function Selection with Watchdog Daisy Chain
3: DynamicFunction SelectionwithLimitMonitor
4: Static Function Selectionwith Fault Monitor
5: Static Function Selection with Watchdog Monitor
6: Static Function Selection with Watchdog Daisy Chain
7: Static FunctionSelectionwithLimit Monitor
Table2:OperatingModes
The EPC has eight (8) operating modes. For Dynamic Modes, the EPC will dynamically select
the active function program based on the state of the digital input and the Program Block
settings. For Static Modes, the EPC has only function block 1 active and the digital input may
be used for an alternative purpose defined by that particular mode described in the following
sections.
The digital output is always controlled by the mode specification.
Note: Firmware versions prior to 1.10 only support Modes 0, 1 and 2.
6

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
Telephone: [phone] Oilgear
Fax: [phone] International Dr Issued May 31, 2018
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4.1.2.1DynamicFunctionSelectionwithFaultMonitor
This operating mode is selected by setting program item 200 to 0 by choosing Mode 0:
Dynamic Function Selection with Fault Monitor fromthe General Configuration Form.
In this operating mode, the digital input selects which program block is active. If the digital
input is low (<5 VDC), Program Block 1 is made active and the program defined in program
item 210 is used. If the digital input is high (> 5VDC), Program Block 2 is made active and the
program defined in program item 211 is used. Refer to Section 4.1.3 for discussion of Program
Block Configuration (21x).
The digital output provides standard condition status. If no faults are present, the digital output
will be high (VSupply); If faults are present, the digital output will be low (0 VDC). Refer to
Section 5.5 for information on module fault and message conditions.
4.1.2.2DynamicFunctionSelectionwith WatchdogMonitor
This operating mode is selected by setting program item 200 to 1 by choosing Mode 1: Dynamic
Function Selection with Watchdog Monitor from the General Configuration Form of the PC
Interface.
In this operating mode, the digital input selects which program block is active. If the digital
input is low (<5 VDC), Program Block 1 is made active and the program defined in program
item 210 is used. If the digital input is high (> 5VDC), Program Block 2 is made active and the
program defined in program item 211 is used. Refer to Section 4.1.3 for discussion of Program
Block Configuration (21x).
The digital output provides a watchdog signal of approximately 100 Hz.
4.1.2.3StaticFunctionSelectionwithWatchdogDaisyChain
This operating mode is selected by setting program item 200 to 2 by choosing Mode 2: Static
Function Selection with Watchdog Daisy Chain from the General Configuration Form.
In this operating mode, Program Block 1 is always active and the program defined in program
item 210 is used. Program Block 2 is always inactive and program item 211 has no function.
Refer to Section 4.1.3 for discussion of Program Block Configuration (21x).
The digital input is passed through the module into the digital output. In this way, one single
watchdog timer can be used for a number of EPC modules. One EPC module would need to be
configured for Mode 1: Dynamic Function Selection with Watchdog Monitor; the remaining
EPCs would be configured for Mode 2. Any module failure would break the daisy chain.

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
Telephone: [phone] Oilgear
Fax: [phone] International Dr Issued May 31, 2018
Web Site: www.oilgear.com Traverse City, MI USA 49686 Bulletin836260F
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4.1.2.4DynamicFunctionSelectionwith LimitMonitor
This operating mode is selected by setting program item 200 to 3 by choosing Mode 3:
Dynamic FunctionSelection with Limit Monitor from the General Configuration Form.
In this operating mode, the digital input selects which program block is active. If the digital
input is low (<5 VDC), Program Block 1 is made active and the program defined in program
item 210 is used. If the digital input is high (> 5VDC), Program Block 2 is made active and the
program defined in program item 211 is used. Refer to Section 4.1.3 for discussion of Program
Block Configuration (21x).
The digital output provides a signal as to whether the stroke command is being limited due to an
over-Power or over-Pressure condition. The over-Power condition is specified from the
Horsepower Limiter. The only supported over-Pressure condition is specified by the Flow with
Pressure Limit Control algorithm (Generation 2).
If either limiting condition is taking place, the digital output will be low (0 VDC). If no limiting
situation is taking place, the digital output will be high (Vsupply). If the Horsepower limiter is
disabled and a program other than a Flow with Pressure Limit Control program (Generation 2) is
active, the digital output will behigh.
4.1.2.5 StaticFunctionSelectionwithFaultMonitor
This operating mode is selected by setting program item 200 to 4 by choosing Mode 4: Static
Function Selection with Fault Monitor from the General Configuration Form of the PC
Interface.
In this operating mode, Program Block 1 is always active and the program defined in menu
210 is used. Program Block 2 is always inactive and menu item 211 has no function.
The digital output provides standard condition status. If no faults are present, the digital output
will be high (VSupply); If faults are present, the digital output will be low (0 VDC).
4.1.2.6StaticFunctionSelectionwithWatchdogMonitor
This operating mode is selected by setting menu item 200 to 5, or by choosing Mode 5: Static
Function Selection with Watchdog Monitor from the General Configuration form of the PC
Interface.
In this operating mode, Program Block 1 is always active and the program defined in menu
210 is used. Program Block 2 is always inactive and menu item 211 has no function.
The digital output provides a watchdog signal of approximately 100 Hz.

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
Telephone: [phone] Oilgear
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4.1.2.7StaticFunctionSelectionwithWatchdogDaisyChain
This operating mode is selected by setting menu item 200 to 6 by choosing Mode 6: Static
Function Selection with Watchdog Daisy Chain from the General Configuration form of the
PC Interface.
In this operating mode, Program Block 1 is always active and the program defined in menu
210 is used. Program Block 2 is always inactive and menu item 211 has no function.
The digital input is passed through the module into the digital output. In this way, one single
watchdog timer can be used for a number of EPC modules. One EPC module would need to be
configured for Mode 1 (Dynamic Function Selection with Watchdog Monitor) while the
remaining EPCs would be configured for Mode 2. Any module failure would break the daisy
chain.
4.1.2.8StaticFunctionSelection withLimitMonitor
This operating mode is selected by setting menu item 200 to 7, by choosing Mode 7: Static
Function Selection with Limit Monitor from the General Configuration form of the PC
Interface.
In this operating mode, Program Block 1 is always active and the program defined in menu
210 is used. Program Block 2 is always inactive and menu item 211 has no function.
The digital output provides a signal as to whether the stroke command is being limited due to an
over-Power or over-Pressure condition. The over-Power condition is specified from the
Horsepower Limiter. The only supported over-Pressure condition is specified by the Flow with
Pressure Limit Control algorithm (Generation 2).
If either limiting condition is taking place, the digital output will be low (0 VDC). If no limiting
situation is taking place, the digital output will be high (VSupply). If the Horsepower limiter is
disabled and a program other than a Flow with Pressure Limit Control program (Generation 2) is
active, the digital output will behigh.

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
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4.1.3ProgramBlockConfiguration(21x)
Program Item Range Description
210 0 to 12 Program Selection for Program Block 1
0: No Program used for Block 1
(refer to Section 4.3.2.1)
1-12: Program 1 to 12 used for Block 1
211 0 to 12 Program Selection for Program Block 2
0: No Program used for Block 2
(refer to Section 4.3.2.1)
1 to12: Program 1 to 12 used for Block 2
Table3:ProgramBlockConfiguration
The program block configuration parameters are used in conjunction with the module operating
modes to assign pre-defined programs to the two (2) program blocks.
Dynamic Operating Modes: These modes are referred to as “dynamic” because the digital input
selects which Program Block is active. If the digital input is low (<5 VDC), Program Block 1 is
made active and the program defined in menu 210 is used. If the digital input is high (> 5VDC),
Program Block 2 is made active and the program defined in menu 211 is used (see Example).
Static Operating Modes: These modes are referred to as “static” because Program Block 1 is
always active and menu 210 defines the active function program. Menu 211 has no function in
operating mode 2. The static operating modes also free the digital input to be used for a function
other than program selection.

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
Telephone: [phone] Oilgear
Fax: [phone] International Dr Issued May 31, 2018
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Figure3:GeneralConfigurationForm
Example 1: Operating Mode (program item 200) is set to 0 (Dynamic Function Selection with
Fault Monitor). Program Selection for Program Block 1 (program item 210) is set to 1 (Pressure
Control) and Program Selection for Program Block 2 (program item 211) is set to 3 (Flow with
Pressure Limit Control). See Figure 3.
If the digital input is low (<5 VDC), Program Block 1 is made active and the active program is
Program 1 (Pressure Control). If the digital input is high (> 5VDC), Program Block 2 is made
active and the active program is Program 3 (Flow with Pressure Limit Control).
Example 2: Again, operating Mode is set to 0. Program Selection for Program Block 1 (program
item 210) is set to 1 (Pressure Control) and Program Selection for Program Block 2 (program
item 211) is set to 0 (No Program).
If the digital input is low (<5 VDC), Program Block 1 is made active and the active program is
Program 1 (Pressure Control). If the digital input is high (> 5VDC), Program Block 2 is made
active, but since no program is activated, the module uses a special zero function command to
command the pump controller (refer to Section 4.3.2.1 for configuration of the Function Zero
Stroke Command).
Mode2: For operating mode 2 (Static Function Selection with Watchdog Daisy Chain) the digital
input is used as a watchdog input signal. Therefore, no dynamic function selection is possible. In
this mode, Program Block 1 is always active and program item 210 defines the active function
program. Program item 211 has no function in operating mode 2.
The program blocks are selected from the General Configuration Form.
4.1.4EPCHardwareandSoftwareInformation
After an upload from the EPC to a PC, several non-editable parameters are shown in the General
Configuration Form. These items include the model, serial number, software version and hardware
version. See Figure 3.
11

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
Telephone: [phone] Oilgear
Fax: [phone] International Dr Issued May 31, 2018
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4.1.5USBCommunication
The PC software interface must be configured properly to communicate to the EPC module. The
EPC should be connected via the USB-B connecter on the front of the device, and it carries an
internal USB-232 converter, but if necessary, download the appropriate driver from
http://www.ftdichip.com/drivers/VCP.htm. The COM port number will be assigned when the
driver installs (check your device manager for that COM port #) and baud rate is listed on the
General Configuration Form. See Figure 3.
4.1.6 Update Rate
The PC interface will update on-line information as quickly as possible. Often times this can be
improved bylimiting the number of Windows™ applications. Typically, the EPC update rate will be
maximized in the 2 to 3 Hz range. See Figure 3.
4.2ProgramConfiguration
4.2.1Overview
The EPC offers 12 pre-defined programs. The programs range from simple flow control to
advanced functionality. Six different types of programs exist, and the module provides two distinct
copies of each program.
Programs 1 and 2 provide Pressure Control programs. Programs 3 and 4 provide Flow with
Pressure Limit Control programs. Programs 5 and6 provide Load Sense Control programs.
Programs 7 and 8 provide Simple Flow Control programs. Programs 9 and 10 provide Pressure
Control with Flow Preset programs. Finally, Programs 11 and 12 provide Advanced Control with
Feed-Forward.
Programs 3, 4, 9, and 10 have been modified since the manual 3 revisions ago (Bulletin 83260A) to
improve performance. This software enhancement is called Generation 2. It requires EPC software
versions 1.07 or later and PC Interface software version 1.55.0014 or later. See Appendix A for
Generation 1 information.
Programs 11 and 12 require EPC software versions 1.10 or later and PC Interface software
version 1.20 or later.
Under usual circumstances, the pre-defined programs are used as outer loop control. The output of
the pre-defined programs is normally passed through to the Pump Controller module (refer to
Section 4.3.1 for an overview of the Pump Controller).
4.2.2PIControlAlgorithms
Most programs use a PI(Proportional with Integral) control scheme. Although an advanced tutorial on
digital control systems is beyond the scope ofthis technical document some level of knowledge and
experienceis necessarytosuccessfullyimplementthecontrolprograms.
The basis of a PI controller is that an output signal is produced due to a difference between a
command and feedback term (the difference is usually referred to as Error). The output signal
for a PI control is made of a proportional error signal combined with an integral error signal.

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
Telephone: [phone] Oilgear
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4.2.3PressureControlPrograms (40x,41x)
Program Item Range Description
400 1 to 100 Program 1: Pressure Command Preset
401 0 to 5 Program 1: Pressure Command Source
402 1 to 5 Program 1: Pressure Feedback Source
403 0 to 1 Program1:ProgramOutput Destination
404 0 to 100 Program 1: KP
405 0 to 100 Program 1: KI
410 1 to 100 Program 2: Pressure Command Preset
411 0 to 5 Program 2: Pressure Command Source
412 1 to 5 Program 2: Pressure Feedback Source
413 0 to 1 Program2:ProgramOutput Destination
414 0 to 100 Program 2: KP
415 0 to 100 Program 2: KI
Table 4: Pressure Control Programs Configuration
Function Programs 1 and 2 provide for basic Pressure Control. Program 1 is configured in program
items 400 through 405 or from the Program 1 Form. Program 2 is configured in program items 410
through 415 from the Program 2 Form.
Pressure Command Preset: The Pressure Command Preset allows for direct numeric input for the
control program. The preset is configured as a percentage, with 0% being equivalent to a 0VDC input
signaland100%beingequivalent toa +10VDC signal.
Pressure Command Source: The Pressure Command Source selects the source of the pressure
command for the program. Valid entries are (0) Preset Value, (1) Analog Input 1, (2) Analog Input
2, (3) Analog Input 3, (4) LVDT 1 (Analog Input 4), or (5) Ramp 1. If the Preset Value is chosen,
the Pressure Command Preset is used as the program command.
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
Programwillbe theinputtothe PumpController module. If Directischosen,the outputof 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 and KI: KP and KI provide the proportional and integral constants, respectively, for the PI
control algorithm. Both terms are expressed as 0 to 100% of a maximum value. The PI control
loop can be made a P-only control loop by setting the KI term to 0. Likewise, the PI control loop
can be made an I-only control loop by setting the KP term to 0.

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
Telephone: [phone] Oilgear
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Program Overview: The Pressure Control Program is a straightforward PI control
algorithm. Comparing the command to the feedback value produces an error value.
The error is multiplied by the KP and KI constants to produce the Yp and Yi
contributions to the program output.
Figure 4: Pressure Control
Program
Example: Figure 4 shows the Program 1 Form for Pressure Control. The Pressure
Command Source is Analog Input 1 (program item 401=1) and the Pressure Feedback
Source is Analog Input 2 (program item 402=2). The Pressure Command Preset has a
value of 50% (program item 400=50) although it is not used for this particular example.
The error signal is produced by comparing the command to the feedback signals:
4.91V - 4.05V = 0.86V. The Yi and Yp signals are produced from the PI controller and the
program output is roughly equal to their sum: 8.00V + 0.66V = 8.66V. The Program
Output is set to the Pump Controller (program item 403=0).

EPC
SERVO AMPLIFIER MODULE
Part Number L723888-3xx
ELECTRONIC
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4.2.4FlowwithPressureLimit Programs-Generation2(42x,43x)
ProgramItem Range Description
420 0 to 100 Program3: Flow Command Preset
421 1 to 100 Program 3: Pressure Limit Preset
422 0 to 5 Program 3: Flow Command Source
423 0 to 5 Program 3: Pressure Limit Source
424 1 to 5 Program 3: Pressure Feedback Source
425 0 to 1 Program3:ProgramOutput Destination
426 0 to 100 Program 3: KP
427 0 to 100 Program3: FullScaleCommand
428 0 to 100 Program 3: Pressure Breakpoint Preset
429 0 to 7 Program 3: Pressure Breakpoint Source
430 0 to 100 Program4: Flow Command Preset
431 1 to 100 Program 4: Pressure Limit Preset
432 0 to 5 Program 4: Flow Command Source
433 0 to 5 Program 4: Pressure Limit Source
434 1 to 5 Program 4: Pressure Feedback Source
435 0 to 1 Program4:ProgramOutput Destination
436 0 to 100 Program 4: KP
437 0 to 100 Program4: FullScaleCommand
438 0 to 100 Program 4: Pressure Breakpoint Preset
439 0 to 7 Program 4: Pressure Breakpoint Source
Table 5: Flow with Pressure Limit Programs
Function Programs 3 and 4 provide for Flow with Pressure Limit Control. Program 3 is configured in
program items 420 through 429 in the Program 3 Form. Program 4 is configured in program items
430 through 439 in the Program 4 Form.
Flow Command Preset: The Flow Command Preset allows for direct numeric input for the control
program. The preset is configured as a percentage, with 0% being equivalent to a 0VDC input signal
and100%beingequivalentto a+10VDCsignal.
Pressure Limit Preset: The Pressure Limit Preset allows for direct numeric input for the control
program. The preset is configured as a percentage, with 0% being equivalent to a 0VDC input
signaland100%beingequivalent toa +10VDC signal.
Flow Command Source: The Flow Command Source selects the source of the flow command for
the program. Valid entries are (0) Preset Value, (1) Analog Input 1, (2) Analog Input 2, (3) Analog
Input 3), (4) LVDT 1 (Analog Input 4), or (5) Ramp 1. If the Preset Value is chosen, the Flow
Command Preset is used as the flow command.
Pressure Limit Source: The Pressure Limit Source selects the source of the pressure limit command
for the program. Valid entries are (0) Preset Value, (1) Analog Input 1, (2) Analog Input
2, (3) Analog Input 3, (4) LVDT 1 (Analog Input 4), or (5) Ramp 1. If the Preset Value is chosen,
the Pressure Limit Preset is used as the pressure limit command.

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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
Programwillbe theinputtothe PumpController module. If Directischosen,the outputof 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: KPprovides theproportional gain settingto control the pressure limit slope. KP is configured as
a percentage, with 0% to noproportional gain and100% equivalent tomaximumproportional gain.
Pressure Breakpoint Preset: The Pressure Breakpoint Preset allows for direct numeric input. The
preset has a slightly different characteristics depending on the value of itsentry.
If the Pressure Breakpoint Source is set to 0 (Preset Value), the preset is configured as a
percentage, with 0% equivalent toa 0VDC input signaland 100% equivalent toa +10VDC signal.
This value is used as the Pressure Breakpoint command.
If the Pressure Breakpoint Source is set to 6 (Limit Offset), the preset is configured as a
percentage, with 0% equivalent toa 0VDC input signaland 100% equivalent toa -10VDC offset
signal. The offset value is added to the Pressure Limit Source signal to make the Pressure
Breakpointcommand.
Finally, if the Pressure Breakpoint Source is set to 7 (Limit Attenuation), the preset is configured as
a percentage of the Pressure Limit Source, with 0% equivalent to a 0VDC input signal and 100%
equivalent to the Pressure Limit Source. This value is used as the Pressure Breakpoint command.
Pressure Breakpoint Source: The Pressure Breakpoint Source selects the source of Pressure
Breakpoint 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, (7) Limit Attenuation, (8) Reference
Offset or (9) Reference Attenuation.
ProgramOverview:TheFlowwithPressureLimit Control Programisa slopingpressure limiting
controlprogramsimilartothe control schemes used inOilgear AnalogRacksystems.
The algorithm will begin tolimit the Flow command once the Pressure Feedback value is greater than
the Pressure Breakpoint command. Comparing the Breakpoint command to the Feedback value
produces an error value. The error is multiplied by the KP constant to produce the Yp limit signal,
which is summed with the full-scale command. The summation of the full-scale command and the
YP limit signal in turn sets a limit to the Flow command. If the Breakpoint Pressure Limit command
is greater thanthe Feedback signal, the Flow command will only be limited bythe full- scale
command.
If using EPC software version 1.06 or earlier, see Appendix A for Generation 1 control.

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Figure5:FlowwithPressureLimitProgram
Example: Figure 5 shows Program 3 Form for Flow with Pressure Limit. The Flow Command
Source is Analog Input 1 (program item 422=1). The Flow Command Preset is set to 10%
(program item 420=10) although the Flow Command Preset is not used inthis example.
The Pressure Limit Source command is the Preset Value (program item 423=0), therefore the
pressure limit command is set at a 70% level (program item 421=70). The Pressure Feedback
Sourceis Analog Input 2 (program item 424=2).
The Pressure Breakpoint Source is Limit Offset (program item 429=6). The Pressure Breakpoint
Preset is set to 10% (program item 428=10). The Pressure Breakpoint value is the Pressure Limit
minus the Pressure Breakpoint Preset: 7.00V-1.00V = 6.00V. Note there is a slight conversion error
in this example. The Pressure Limit Preset is 70 but at the Pressure Limit Source it is 6.99V instead
of 7.00V.
The error signal is produced by comparing the Pressure Breakpoint Source to the Feedback signal:
6.00V - 6.95V = -0.95V. The error is multiplied by the KP constant to produce the Yp limit
-0.95V x 10.26 = -9.75V. A KP value of 64 equals a 10.26 KP constant.
The Pressure Limit command is summed with the Full-Scale command to set the limit for the Flow
command: 10.0V - 9.75V = 0.25V. Finally, the Program Output is set to the Pump Controller
(programitem425=0).

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4.2.5 Load SenseControl Programs (44x,45x)
Program Item Range Description
440 1 to 100 Program 5: Pressure Point 2 Preset
441 1 to 100 Program 5: Delta Pressure Preset
442 1 to 100 Program 5: Pressure Limit Preset
443 0 to 5 Program 5: Pressure Point 2 Source
444 0 to 5 Program 5: Delta Pressure Source
445 0 to 5 Program 5: Pressure Limit Source
446 1 to 5 Program 5: Pressure Point 1 Source
447 0 to 1 Program5:ProgramOutput Destination
448 0 to 100 Program 5: KP
449 0 to 100 Program 5: KI
450 1 to 100 Program 6: Pressure Point 2 Preset
451 1 to 100 Program 6: Delta Pressure Preset
452 1 to 100 Program 6: Pressure Limit Preset
453 0 to 5 Program 6: Pressure Point 2 Source
454 0 to 5 Program 6: Delta Pressure Source
455 0 to 5 Program 6: Pressure Limit Source
456 1 to 5 Program 6: Pressure Point 1 Source
457 0 to 1 Program6:ProgramOutput Destination
458 0 to 100 Program 6: KP
459 0 to 100 Program 6: KI Table 6: Load Sense Programs Configuration
Function Programs 5 and 6 provide for Load Sense Control. Program 5 is configured in program
items 440 through 449 from the Program 5 Form. Program 6 is configured in program items 450
through 459 from the Program 6 Form.
Pressure Point 2 Preset: The Pressure Point 2 Preset allows for direct numeric input for the
control program. The preset is configured as a percentage, with 0% being equivalent to a 0VDC
inputsignaland100%beingequivalent toa +10VDC signal.
DeltaPressurePreset: The Delta Pressure Preset allows for direct numeric inputfor the control
program. The preset is configured as a percentage, with 0% being equivalent to a 0VDC input
signaland100%beingequivalent toa +10VDC signal.
Pressure Limit Preset: The Pressure Limit Preset allows for direct numeric input for the control
program. The preset is configured as a percentage, with 0% being equivalent to a 0VDC input
signaland100%beingequivalent toa +10VDC signal.

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Pressure Point 2 Source: The Pressure Point 2 Source selects the source of the pressure point
2 signal for the program. Valid entries are (0) Preset Value, (1) Analog Input 1, (2) Analog Input
2, (3) Analog Input 3, (4) LVDT 1 (Analog Input 4), or (5) Ramp 1. If the Preset Value is chosen,
the Pressure Point 2 Preset is used as the delta pressure point 2 command.
Delta Pressure Source: The Delta Pressure Source selects the source of the delta pressure signal
for the program. Valid entries are (0) Preset Value, (1) Analog Input 1, (2) Analog Input 2, (3)
Analog Input 3), (4) LVDT 1 (Analog Input 4), or (5) Ramp 1. If the Preset Value is chosen, the
Delta Pressure Preset is used as the delta pressure command.
Pressure Limit Source: The Pressure Limit Source selects the source of the pressure limit
command for the program. Valid entries are (0) Preset Value, (1) Analog Input 1, (2) Analog Input
2, (3) Analog Input 3, (4) LVDT 1 (Analog Input 4), or (5) Ramp 1. If the Preset Value is chosen,
the Pressure Limit Preset is used as the pressure limit command.
Pressure Point 1 Source: The Pressure Point 1 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
Programwillbe theinputtothe PumpController module. If Directischosen,the outputof 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 and KI: KP and KI provide the proportional and integral constants, respectively, for the PI
control algorithm. Both terms are expressed as 0 to 100% of a maximum value. The PI control
loop can be made a P-only control loop by setting the KI term to 0. Likewise, the PI control loop
can be made an I-only control loop by setting the KP term to 0.
Orifice
Figure6:LoadSenseCircuit
Δ P = P1 - P2
EPC
Pressure P1
Pressure P2
P P
U U

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Program Overview: The Load Sense Control Program is one of the more complex control
algorithms supplied with the EPC. The goal of the load sense control is to maintain a pressure
difference across an orifice (refer to Figure 6). Typically, two pressure transducers would be used to
monitor two points in the hydraulic circuit. The pump flow would be controlled such that P = P1 -
P2.
In addition to this basic control, a pressure limiter is added to ensure that the down-flow pressure at P2
does not reach a critical point. The controller command is the sum of the Point 2 Pressure and Delta
Pressuresignals,limited bythe Pressure Limit Command. Comparingthis command withthe Point 1
Pressure signal results in an error value. The error is multiplied by the KP and KI constants to
produce the Yp and Yi contributions to the program output signal.
Figure 7: Load Sense Program
Example: Figure 7 shows Program 5 Form for Load Sense. The Delta Pressure Source is set to the
Delta Pressure Preset Value of 10% (program item 444=0 and program item 441=10). The Pressure
Point 2 Source is Analog Input 1 (program item 443=1), therefore the command is 1.00V
+1.54V = 2.54V.
The Pressure Limit Source is set to the Pressure Limit Preset Value of 50% (program item 445=0
and program item 442=50). In this case, the previous command value is not limited, since the
command (2.54V) is less than the Pressure Limit Command (5.00V).
The error signal is produced by comparing the Command to the Pressure Point 1 signals: 2.54V -
2.24V = 0.30V. The Yi and Yp signals are produced from the PI controller and the Program Output is
roughly equal to their sum: 5.00V + 0.24V = 5.24V. The Program Output is set to the Pump
Controller(programitem447=0).