WEST PAM-198-P Guide

Technical Documentation
PAM-198-P
Power amplifier for directional valves with feedback position control

Page 2 of 33 PAM-198-P 05.06.2020
CONTENTS
1General Information......................................................................................................................................................4
1.1 Order Number.......................................................................................................................................................4
1.2 Scope of supply....................................................................................................................................................4
1.3 Accessories..........................................................................................................................................................4
1.4 Symbols used.......................................................................................................................................................5
1.5 Legal notice..........................................................................................................................................................5
1.6 Safety instructions................................................................................................................................................6
2Characteristics..............................................................................................................................................................7
2.1 Device description................................................................................................................................................8
3Use and application......................................................................................................................................................9
3.1 Installation instruction...........................................................................................................................................9
3.2 Typical system structure.....................................................................................................................................10
3.3 Method of operation............................................................................................................................................11
3.4 Commissioning...................................................................................................................................................12
4Function modes and technical description.................................................................................................................. 13
4.1 Input and output signals .....................................................................................................................................13
4.2 LED Indications ..................................................................................................................................................13
4.3 Circuit diagram ...................................................................................................................................................14
4.4 Typical wiring......................................................................................................................................................15
4.5 Input connection (examples)...............................................................................................................................15
4.6 Technical data....................................................................................................................................................16
5Parameter................................................................................................................................................................... 17
5.1 Parameter list .....................................................................................................................................................17
5.2 Basic parameters................................................................................................................................................19
5.2.1 LG (Changing the language for the help texts) ..........................................................................................19
5.2.2 MODE (Selecting visible parameter group)................................................................................................19
5.2.3 CTRLMODE (activation spool positioning control).....................................................................................19
5.2.4 CCMODE (Activation of the characteristic linearization)............................................................................20
5.2.5 SENS (Failure monitoring).........................................................................................................................20
5.3 Input signal adaption ..........................................................................................................................................21
5.3.1 AIN (Analogue input scaling) .....................................................................................................................21
5.3.2 SIGNAL:U (Type and polarity of the control signal) ...................................................................................22
5.3.3 VA:OFFSET (Zero point setting)................................................................................................................22
5.3.4 VA:MIN (Minimum control).........................................................................................................................23
5.3.5 VA:MAX (Maximum control).......................................................................................................................23
5.3.6 VA:TRIGGER (Response threshold for the MIN parameter)......................................................................23
5.4 Signal processing...............................................................................................................................................24
5.4.1 RA (Ramp function) ...................................................................................................................................24
5.4.2 CC (Characteristics linearization) ..............................................................................................................25
5.4.3 MIN (Overlap compensation).....................................................................................................................26
5.4.4 MAX (Output scaling).................................................................................................................................26
5.4.5 TRIGGER (Threshold value of MIN function).............................................................................................26
5.5 Parameters of the closed loop controller ............................................................................................................27
5.5.1 PID controller.............................................................................................................................................27
5.5.2 Integrator control........................................................................................................................................28
5.6 Parameters of the power stage...........................................................................................................................29
5.6.1 CURRENT (Nominal solenoid current) ......................................................................................................29
5.6.2 DAMPL (Dither amplitude).........................................................................................................................29
5.6.3 DFREQ (Dither frequency).........................................................................................................................29
5.6.4 PWM (PWM frequency).............................................................................................................................29

Page 3 of 33 PAM-198-P 05.06.2020
5.6.5 ACC (Auto adaptation of the closed loop current controller)......................................................................30
5.6.6 PPWM (Solenoid current controller P gain)................................................................................................30
5.6.7 IPWM (Solenoid current controller I gain) ..................................................................................................30
5.7 Process data (Monitoring)...................................................................................................................................31
6Appendix.....................................................................................................................................................................31
6.1 Failure monitoring...............................................................................................................................................31
6.2 Troubleshooting..................................................................................................................................................32
7Notes..........................................................................................................................................................................33

Page 4 of 33 PAM-198-P 05.06.2020
1 General Information
1.1 Order Number
PAM-198-P - power amplifier for directional valves with feedback position control
1.2 Scope of supply
The scope of supply includes the module plus the terminal blocks which are a part of the housing.
The Profibus plug, interface cables and further parts which may be required should be ordered separately.
This documentation can be downloaded as a PDF file from www.w-e-st.de.
1.3 Accessories
WPC-300 - Start-Up-Tool (downloadable from our homepage –products/software)
Any standard cable with USB-A and USB-B connector can be used as the programming cable.

Page 5 of 33 PAM-198-P 05.06.2020
1.4 Symbols used
General information
Safety-related information
1.5 Legal notice
W.E.St.
Elektronik GmbH
Gewerbering 31
D-41372 Niederkrüchten
Tel.: +49 (0)2163 577355-0
Fax.: +49 (0)2163 577355 -11
Homepage: www.w-e-st.de
EMAIL: contact@w-e-st.de
Date: 05.06.2020
The data and characteristics described herein serve only to describe the product. The user is required to
evaluate this data and to check suitability for the particular application. General suitability cannot be inferred
from this document. We reserve the right to make technical modifications due to further development of the
product described in this manual. The technical information and dimensions are non-binding. No claims may
be made based on them.
This document is protected by copyright.

Page 6 of 33 PAM-198-P 05.06.2020
1.6 Safety instructions
Please read this document and the safety instructions carefully. This document will help to define the product
area of application and to put it into operation. Additional documents (WPC-300 for the start-up software) and
knowledge of the application should be taken into account or be available.
General regulations and laws (depending on the country: e.g. accident prevention and environmental protec-
tion) must be complied with.
These modules are designed for hydraulic applications in open or closed loop control circuits.
Uncontrolled movements can be caused by device defects (in the hydraulic module or the
components), application errors and electrical faults. Work on the drive or the electronics must
only be carried out whilst the equipment is switched off and not under pressure.
This handbook describes the functions and the electrical connections for this electronic as-
sembly. All technical documents which pertain to the system must be complied with when
commissioning.
This device may only be connected and put into operation by trained specialist staff. The in-
struction manual must be read with care. The installation instructions and the commissioning
instructions must be followed. Guarantee and liability claims are invalid if the instructions are
not complied with and/or in case of incorrect installation or inappropriate use.
CAUTION!
All electronic modules are manufactured to a high quality. Malfunctions due to the failure of
components cannot, however, be excluded. Despite extensive testing the same also applies
for the software. If these devices are deployed in safety-relevant applications, suitable external
measures must be taken to guarantee the necessary safety. The same applies for faults which
affect safety. No liability can be assumed for possible damage.
Further instructions
The module may only be operated in compliance with the national EMC regulations. It is
the user’s responsibility to adhere to these regulations.
The device is only intended for use in the commercial sector.
When not in use the module must be protected from the effects of the weather, contamina-
tion and mechanical damage.
The module may not be used in an explosive environment.
To ensure adequate cooling the ventilation slots must not be covered.
The device must be disposed of in accordance with national statutory provisions.

Page 7 of 33 PAM-198-P 05.06.2020
2 Characteristics
This module is used for the control of the spool position of directional valves with electrical feedback. Various
adjustable parameters allow for an optimized adaptation to the respective valve. The integrated power ampli-
fier with a short cycle time of 0,125 ms for the current loop is an inexpensive and space-saving solution. The
closed loop of the application works with a sample time of 1 ms.
Command value and feedback value are read in via free scalable analog inputs (voltage signals in the range
of 0… 10V or +/-10V respectively current signals in the range of 4… 20mA). The output current is closed loop
controlled and therefore independent from the power supply and the solenoid resistance. The output stage is
monitored for cable breakdown, is short circuit proof and disables the power stage in case of an error.
RAMP, MIN and MAX, the DITHER (frequency and amplitude) and the PWM frequency are programmable.
In addition, the valve characteristics can be linearized via 10 XY-points.
Features
Control of directional valves with spool position feedback
Compact housing
Digital reproducible adjustments
Free scaling of the analogue inputs
PID controller with feed forward function
Controlling valves with one or two solenoids
Bipolar controlling via differential input
Characteristics linearization via 10 XY-points per direction
Free parameterization of RAMPS, MIN und MAX, output current, DITHER (frequency, amplitude)
Nominal output current range up to 2.6 A
Simple and application orientated parameter settings via WPC-software
Failure monitoring and extended function check

Page 8 of 33 PAM-198-P 05.06.2020
2.1 Device description
V:
ID:
Add.:Date:
Made in Germany
W.E.ST.
Ready
1 2 3 4
5 6 7 8
910 11 12
14 15 1613
D-41372 Niederkrüchten
Homepage: http://www.w-e-st.de
W.E.ST.
Elektronik
13 14 15
910 11 12
16
A B
Klemmblöcke (steckbar)
Terminals (removable)
LEDs
USB
interface
Typenschild undAnschlussbelegung
Type plate and terminal pin assignment
23,0000 mm99,0000 mm
114,0000 mm

Page 9 of 33 PAM-198-P 05.06.2020
3 Use and application
3.1 Installation instruction
This module is designed for installation in a shielded EMC housing (control cabinet). All cables which
lead outside must be screened; complete screening is required. It is also a requirement that no strong
electro-magnetic interference sources are installed nearby when using our open and closed loop con-
trol modules.
Typical installation location: 24V control signal area (close to PLC)
The devices must be arranged in the control cabinet so that the power section and the signal section
are separate from each other.
Experience shows that the installation space close to the PLC (24 V area) is most suitable. All digital
and analogue inputs and outputs are fitted with filters and surge protection in the device.
The module should be installed and wired in accordance with the documentation bearing in mind EMC
principles. If other consumers are operated with the same power supply, a star-connected ground wir-
ing scheme is recommended. The following points must be observed when wiring:
The signal cables must be laid separately from power cables.
Analogue signal cables must be screened.
All other cables must be screened if there are powerful interference sources (frequency
converters, power contactors) and cable lengths > 3m. Inexpensive SMD ferrites can be
used with high-frequency radiation.
The screening should be connected to PE (PE terminal) as close to the module as possi-
ble. The local requirements for screening must be taken into account in all cases. The
screening should be connected to at both ends. Equipotential bonding must be provided
where there are differences between the connected electrical components.
With longer lengths of cable (>10 m) the diameters and screening measures should be
checked by specialists (e.g. for possible interference, noise sources and voltage drop).
Particular care is required with cables of over 40 m in length –the manufacturer should be
consulted if necessary.
A low-resistance connection between PE and the mounting rail should be provided. Transient interfer-
ence is transmitted from the module directly to the mounting rail and from there to the local earth.
Power should be supplied by a regulated power supply unit (typically a PELV system complying with
IEC364-4-4, secure low voltage). The low internal resistance of regulated power supplies gives better
interference voltage dissipation, which improves the signal quality of high-resolution sensors in partic-
ular. Switched inductances (relays and valve coils connected to the same power supply) must always
be provided with appropriate overvoltage protection directly at the coil.

Page 11 of 33 PAM-198-P 05.06.2020
3.3 Method of operation
This power amplifier with integrated spool position control is controlled by an analog command signal. The
ENABLE signal activates the power stage and application functionality and the READY output reports an error
free operation.
In case of an error the power stage gets deactivated and the error is reported by a deactivated READY output
and a flashing READY LED.
The output current is closed loop controlled which leads to a high accuracy and a good dynamic.
Superior controller is the spool position controller. It has a feed forward function for fast reactions when the
command value changes and a switching integrator with parameterizable Deadband in order to avoid limit cy-
cling at the operation point.
The output can be adapted to valves with one or two solenoids.
In open loop control mode the power stage can be controlled by the feed forward function which leads the
command value directly to the output. In closed loop control mode the control deviation and parameterizing of
the controller define the output signal.

Page 12 of 33 PAM-198-P 05.06.2020
3.4 Commissioning
Step
Task
Installation
Install the device in accordance with the circuit diagram. Ensure it is wired correctly
and that the signals are well shielded. The device must be installed in a protective
housing (control cabinet or similar).
Switching on for the first
time
Ensure that no unwanted movement is possible in the drive (e.g. switch off the
hydraulics). Connect an ammeter and check the current consumed by the device. If
it is higher than specified, there is an error in the wiring. Switch the device off imme-
diately and check the wiring.
Setting up communication
Once the power input is correct the PC (notebook) should be connected to the
serial interface. Please see the WPC-300 program documentation for how to set up
communication.
The further start-up is supported by this program.
Pre-parameterization
Now set up the following parameters (with reference to the system design and circuit
diagrams):
The nominal output CURRENT and the typical valve parameters such as DITHER
and MIN/MAX.
The analog inputs with scaling function AIN.
Pre-parameterization is necessary to minimize the risk of uncontrolled movements.
Control signal
Check the control signal with an amp meter. The control signal (the current of the
solenoid) is within the range of 0... 2, 6A. In the actual status it should show approxi-
mately 0 A.
ATTENTION! You can monitor the actual current also in the WPC-300 program.
Switching on the hydrau-
lics
The hydraulics can now be switched on. The module is not yet generating a signal.
Drives should be at a standstill or drift slightly (leave its position at a slow speed) if it
is a proportional valve.
Activating ENABLE
CAUTION! The drive can now leave its position and move to an end position with full
speed or the pressure can reach maximum. Take safety measures to prevent per-
sonal injury and damage.
The valve can now be controlled by the analog command value (depending on the
settings).
Optimizing settings
Now the adjustment can be optimized. The PID controller has to be adapted to the
relative application and its requirements.

Page 13 of 33 PAM-198-P 05.06.2020
4 Function modes and technical description
4.1 Input and output signals
4.2 LED Indications
LEDs
Description of the LED function
GREEN + YELLOW
1. Chasing light (over all LEDs): The bootloader is active. No normal functions are pos-
sible.
2. All LEDs flash shortly every 6 s: An internal data error was detected and corrected
automatically! The module still works regularly. To acknowledge the error the module
has to be cycle powered.
YELLOW + YELLOW
Both yellow LEDs flash oppositely every 1 s: The nonvolatile stored parameters are in-
consistent! To acknowledge the error the data have to be saved with the SAVE command
or the corresponding button in the WPC.
GREEN
Identical to the READY output.
OFF: No power supply or ENABLE is not activated
ON: System is ready for operation
Flashing: Error detected
YELLOW A
Current to the solenoid A; the intensity is proportional to the actual output current.
YELLOW B
Current to the solenoid B; the intensity is proportional to the actual output current.
Connection
Supply
PIN 7
Power supply (see technical data)
PIN 8
0 V (GND) Power supply (ground).
Connection
PWM output
PIN 3 / 4
Current controlled PWM outputs for solenoid A.
PIN 1 / 2
Current controlled PWM outputs for solenoid B.
Connection
Analogue signals
PIN 9 / 10
Command signal input (WA), range +/- 10 V or 4…20 mA, scalable
PIN 14 / 13
Feedback signal input (X), range 0… 10 V or 4… 20 mA, scalable
PIN 11
0 V (GND) reference for the signal inputs
PIN 12
8 V reference voltage output
Connection
Digital inputs and outputs
PIN 15
Enable Input:
This digital input signal initializes the application and the power stage.
PIN 5
READY output:
ON: Module is ready, no errors are detected
OFF: ENABLE is deactivated or an error was detected.

Page 14 of 33 PAM-198-P 05.06.2020
4.3 Circuit diagram
Ready
Enable
USB Type B
to solenoidA
to solenoid B
Power-
supply
Command input
Sensor input
PE via DIN-RAIL
3
4
1
5
15
Digital output
PAM-198-P
9
14
10
13
Valve-
adaption
Digital input
7
8
Control program
PID
controller Power-
stage
ia
2
Input-
scaling
Differential input
12
Reference
voltage
11
ib
Scaling
+UB
GND
u
Ramp
function
wa
Min/Max
function
wr c
e
w
x
-
Lineari-
zation
wcc
DC
DC

Page 15 of 33 PAM-198-P 05.06.2020
4.4 Typical wiring
4.5 Input connection (examples)
3 wire connections e.g. for HAWE valves
3
4
1
2
Solenoid-A
Solenoid-B
8V PIN 12
GND PIN 11
+In PIN 9
-In PIN 10
Potentiometer / Joystick
+In PIN 9 / 14
-In PIN 10 / 13
SPS/ PLC / SENSOR 0... 10 V
8V PIN 12
GND PIN 11
+In PIN 9
-In PIN 10
Joystick 4... 20 mAinput
+In PIN 9 + 14
-In PIN 10 + 13
GND PIN 11
Enable
8765
16151413
1211109
Analogue command
signal input
SolenoidA
4321
0V
Shield
PE
Power Supply
0V
12 V / 24 V
+
-
Analogue feedback
signal input
-
+
Reference voltage output
Ready
Solenoid B
PE
0V
0V

Page 16 of 33 PAM-198-P 05.06.2020
4.6 Technical data
Supply voltage (Ub)
Current requirement
External protection
[VDC]
[mA]
[A]
12… 30 (incl. ripple)
60 + solenoid current
3 medium time lag
Reference output
Voltage
Max. load
[V]
[mA]
8
25
Digital inputs
OFF
ON
Input resistance
[V]
[V]
[kOhm]
< 2
> 10
25
Digital outputs
OFF
ON
Max. output current
[V]
[V]
[mA]
< 2
max. Ub
50
Analog inputs:
Voltage
Input resistance
Current
Burden
Signal resolution
[V]
[kOhm]
[mA]
[Ohm]
[%]
Unipolar/differential
0… 10 / -10… 10
min. 90
4… 20
390
<0.01
PWM output
Max. output current
Frequency
[A]
[Hz]
Wire break and short circuit monitored
2.6
61… 2604 selectable in defined steps
Controller cycle times
Solenoid current control
Pressure control
[µs]
[ms]
125
1
Serial interface
Transmission rate
-
[kBaud]
USB - virtual COM Port
9,6… 115,2
Housing
Material
Flammability class
Snap-on module acc. EN 50022
PA 6.6 polyamide
V0 (UL94)
Weight
[kg]
0,190
Protection class
Temperature range
Storage temperature
Humidity
Vibration resistance
[IP]
[°C]
[°C]
[%]
-
20
-20… 60
-20… 70
< 95 (non-condensing)
IEC 60068-2-6 (Category C)
Connections
Communication
Plug connectors
PE
USB type B
4 x 4-pole terminal blocks
via the DIN mounting rail
EMC
EN 61000-6-2: 8/2005
EN 61000-6-4: 6/2007 + A1:2011

Page 17 of 33 PAM-198-P 05.06.2020
5 Parameter
5.1 Parameter list
Group
Command
Default
Unit
Description
Basic parameters - SYSTEM
MODE
---
-
Switching visible parameter group
LG
EN
-
Language selection
CTRLMODE
CL
-
Open and closed loop selection
CCMODE
OFF
-
Aktivation / Deactivation CC command
SENS
AUTO
-
Failure monitoring
In- and output adaption - IO_CONF
Sensor signal
AIN:X
U0-10
V
Mathematic scaling function sensor
Command signal
AIN:W
U0-10
-
Mathematic scaling function demand
Control signal
SIGNAL:U
2S+
-
Type and polarity of the output signal
One solenoid
VA:OFFSET
0
0,01 %
Zero point setting
Two solenoids
VA:MIN:A
VA:MIN:B
0
0
0,01 %
0,01 %
Minimum control for spring pre-load
VA:MAX:A
VA:MAX:B
10000
10000
0,01 %
0,01 %
Maximum control
VA:TRIGGER
200
0,01 %
Treshold for minimum control
Command signal adaption - ADAPT
Ramp function
RA:1
RA:2
RA:3
RA:4
100
100
100
100
ms
ms
ms
ms
Ramp times for command signal
Linearization function
CC
X Y-
0,01 %
Parameterizing linearization by 10 points
Deadband compensation / direction depending scaling
MIN:A
MIN:B
0
0
0,01 %
0,01 %
Deadband compensation
MAX:A
MAX:B
10000
10000
0,01 %
0,01 %
Output scaling
TRIGGER
200
0,01 %
Treshold for deadband compensation

Page 18 of 33 PAM-198-P 05.06.2020
Group
Command
Default
Unit
Description
Parameterizing the controller - CTRL
PID controller
C:P
C:I
C:D
C:D_T1
C:FF
100
4000
0
500
8000
0,01
0,1 ms
0,1 ms
0,1 ms
0,01 %
P gain
I gain
D gain
D gain filter
Feed forward
Integrator control
C:I_LIM
2500
0,01 %
Working range limitation
C:I_ACT
10000
0,01 %
Activation treshold
C:I_DZ
0
0,01 %
Deadband
Power stage - PAM
CURRENT
1000
mA
Solenoid nominal current
DFREQ
121
Hz
Dither frequency
DAMPL
500
0,01 %
Dither amplitude
PWM
2604
Hz
PWM frequency
ACC
ON
-
Automatical adjustment of the current controller
PPWM
IPWM
7
40
-
-
P-gain of the current controller
I-gain of the current controller

Page 19 of 33 PAM-198-P 05.06.2020
5.2 Basic parameters
5.2.1 LG (Changing the language for the help texts)
Command
Parameters
Unit
Group
LG X
x= DE|EN
-
-
Either German or English can be selected for the help texts in the WPC-300 program.
5.2.2 MODE (Selecting visible parameter group)
Command
Parameters
Unit
Group
MODE X
x= SYSTEM|IO_CONF|ADAPT|
CTRL|PAM|ALL
-
SYSTEM
This command defines the group which parameters should be displayed. Inactive parameters are partially
masked independent from the selected group.
SYSTEM Basic settings of the device or application
IO_CONF Definitions of the input and output signals of the device
ADAPT Signal processing and adaption
CTRL Parameterizing of the position controller
PAM Parameters of the power stage
ALL No selection, all active parameters are visible
5.2.3 CTRLMODE (activation spool positioning control)
Command
Parameters
Unit
Group
CTRLMODE X
x= OL|CL
-
SYSTEM
Switching between Open Loop control mode as simple power amplifier and Closed Loop control mode with
PID controller and connected feedback for spool position control.
In open loop mode the power stage can be controlled directly via the feed forward parameter. This option nor-
mally can only be used for valves which ensure a stable positioning of the spool without electronic control. But
it can also be useful here to optimize the feed forward and offset settings before activating the PID controller.

Page 20 of 33 PAM-198-P 05.06.2020
5.2.4 CCMODE (Activation of the characteristic linearization)
Command
Parameters
Unit
Group
CCMODE X
x= ON|OFF
-
SYSTEM
This command will be used for activation or deactivation of the characteristics linearization. Through deactivat-
ing this parameter a simple and quick estimation of the linearization is possible.
CAUTION: If CC command is used, parameters MIN, MAX and TRIGGER have to be considered.
CC and those commands affect each other. Pay attention to that if it is necessary to use both kind
of settings at the same time. Otherwise try to use only one of this options for those settings.
5.2.5 SENS (Failure monitoring)
Command
Parameters
Unit
Group
SENS X
x= ON|OFF|AUTO
-
SYSTEM
This command is used to activate/deactivate the monitoring functions (4… 20 mA sensors, output current, sig-
nal range and internal failures) of the module.
ON: All monitoring functions are active. Detected failures can be reset by deactivating the ENABLE input.
This mode should be used in case of active enabling and monitoring by a PLC (READY signal).
OFF: No monitoring function is active.
AUTO: Auto reset mode. All monitoring functions are active. If the failure does not exist anymore, the mod-
ule automatically resumes to work.
Normally the monitoring functions are always active because otherwise no errors are detectable via
the READY output. Deactivating is possible especially for troubleshooting.
Table of contents
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