Druck DPI 520 User manual

K163 Issue No. 3
i
DPI 520
RACK MOUNTED PRESSURE CONTROLLER
DPI 520 Pressure Controller
Software Issue
This User Manual supports Software Issue No. 3.XX
©Druck Limited 1998
This document is the property of Druck Limited and may not, either in part or whole, be copied or
otherwise reproduced, communicated in any way to third parties, or stored in any Data Processing
System, without the express written authority of Druck Limited.
DPI 520 User Manual

K163 Issue No. 3
ii DPI 520 User Manual
SAFETY
The Manufacturer has designed this product to be entirely safe when operated
correctly.
●●
●●
●Please pay close attention to the Safety Instructions outlined on this page and
elsewhere in this manual. They have been designed to protect the user from
personal injury and the equipment from damage.
●●
●●
●Potentially hazardous operations are indicated in the text by
means of a hazard warning triangle. Specific warnings
relating to each section of the manual are given at the
beginning of that section. On the instrument, this symbol
indicates that the user should refer to the User Manual.
●●
●●
●Please observe the installation advice and any operational limits given in this
manual.
●●
●●
●This equipment must only be used for the purpose for which it was designed
Pressure Safety
Do not permit pressures greater than the Safe Working Pressure to be applied to
the instrument. The specified Safe Working Pressure for the instrument is stated
in the Specification section of this manual.
Electrical Safety
The instrument is designed to be completely safe when used with Options and
Accessories supplied by the manufacturer for use with the instrument.
Toxic Materials
During normal operation it is not possible for the user to come into contact with any
hazardous substance which might be employed in the construction of the instru-
ment. The use of hazardous materials in the construction of this instrument has
been minimised.

K163 Issue No. 3
iii
Repair and Maintenance
This publication contains information and warnings which must be followed for safe
operation and to maintain the equipment in a safe condition. Use qualified*
personnel and good engineering practice for all procedures in this publication.
The operator must not use this equipment for any other purpose than that stated.
Do not apply a pressure greater than the maximum pressure stated.
* A qualified person must have attended a product training course given by the
manufacturer or appointed agent and successfully completed the training
course on this equipment.
This product meets the essential protection requirements of the
relevant EEC directives. Further details of applied standards may
be found in the product specification.
Safety

K163 Issue No. 3
iv DPI 520 User Manual
ABBREVIATIONS
NOTE: Abbreviations are the same in the singular and plural.
ac alternating current
atm atmosphere
°C degrees Celsius
°F degrees Fahrenheit
COM common
cm2centimetre squared
contd continued
dc direct current
DMM digital multimeter
DUT device under test
ENT enter
FS full-scale
ft feet
kg kilogram
LSD Least significant digit
Pa Pascal
PIN personal identification number
mA milli Amperes
mH2O4 metres of water at 4°C
mm milli metres
MSD most significant digit
N/C No Connection
No. number
PRESS pressure
PTX pressure transmitter
RDG reading
RS 232 serial data transmission standard
SCPI Standard command for programmable
instrumentation
Ttare
VAC vacuum

K163 Issue No. 3
v
Contents
1 INTRODUCTION ............................................................................................. 1-1
1.1 Instrument Specification .................................................................................. 1-2
1.2 Applications ..................................................................................................... 1-6
1.2.1 Control by Remote Computer via IEEE 488 ........................................ 1-6
1.2.2 Control by Remote Computer via RS232 ............................................ 1-7
1.2.3 Control by Remote User Interface ....................................................... 1-7
2 FUNCTIONAL DESCRIPTION ........................................................................ 2-1
2.1 General............................................................................................................ 2-1
2.2 Instruments Electronics ................................................................................... 2-1
2.2.1 Digital Electronics ................................................................................ 2-1
2.2.2 Analogue Circuit Operation .................................................................. 2-3
3 INSTALLATION ............................................................................................... 3-1
3.1 Safety Instruction ............................................................................................ 3-1
3.1.1 Input/Output Connections .................................................................... 3-1
3.1.2 Rack Mounting ..................................................................................... 3-1
3.2 Electrical Connections .................................................................................... 3-3
3.2.1 Electrical Safety Instructions ................................................................ 3-3
3.2.2 Power Supply Connections .................................................................. 3-3
3.3 Communications Interface Connections ......................................................... 3-5
3.4 IEEE 488 Interface .......................................................................................... 3-5
3.4.1 Single Unit Installation ......................................................................... 3-7
3.4.2 Multiple Unit Installation ....................................................................... 3-8
3.5 RS232 Interface .............................................................................................. 3-9
3.5.1 General ................................................................................................ 3-9
3.5.2 Connecting to a Computer ................................................................... 3.11
3.6 Connection of Remote User Interface ............................................................. 3-18
3.7 Analogue Output Socket .................................................................................3-18
3.8 Pressure Connections ..................................................................................... 3-19
3.8.1 Pressure Safety Instructions ................................................................3-19
3.8.2 Connection ........................................................................................... 3-19
3.8.3 Obtaining the Best Performance .....................................................................3-23
3.8.4 Maximising Valve Life .......................................................................... 3-24
3.8.4 Control at Zero Gauge Pressure without a Vacuum Pump ................. 3-25
3.9 Set-up Mode ....................................................................................................3-26
3.9.1 General ................................................................................................ 3-26
3.9.2 Set-up MENU ....................................................................................... 3-28
Keyboard (Unlocked) ................................................................3-28
Recall defaults ........................................................................... 3-29
Set-up controller ........................................................................ 3-30
Set PIN ....................................................................................... 3-32
Show S/W Revision .................................................................. 3-33
Self Test Electronic .................................................................... 3-33
Self Test Pneumatic ................................................................... 3-34
3.9.3 Set-up COMMUNICATIONS ................................................................ 3-36
3.9.4 Set-up More (Scale, Zero, More) ......................................................... 3-45
3.9.5 More (Set-point and Rate) ................................................................... 3-47
.
Section Page

K163 Issue No. 3
vi DPI 520 User Manual
Continued.....
4 OPERATION ................................................................................................... 4-1
4.1 Local Mode ...................................................................................................... 4-1
4.2 Remote Mode .................................................................................................. 4-1
4.3 Control Codes ................................................................................................. 4-1
4.3.1 Control Code Format ........................................................................... 4-2
4.3.2 Implementation of checksums ............................................................. 4-3
4.4 Command Description ..................................................................................... 4-6
4.4.1 Set to Local Mode - 'M' ........................................................................ 4-6
4.4.2 Set Mode - 'R' ...................................................................................... 4-6
4.4.3 Set Scale Unit - 'S' ............................................................................... 4-7
4.4.4 Units - 'U' .............................................................................................. 4-7
4.4.5 Data Select - 'D' ................................................................................... 4-7
4.4.6 Output Data Format - 'N' ...................................................................... 4-7
4.4.7 Interrrupt -'I' ......................................................................................... 4-9
4.4.8 Wait - 'W' ............................................................................................. 4-9
4.4.9 Controller On/Off - 'C' ........................................................................... 4-10
4.4.10 Pressure Set-Point - 'P' ........................................................................ 4-10
4.4.11 Ratio - '/' ............................................................................................... 4-10
4.4.12 Preset - '*' ............................................................................................. 4-10
4.4.13 Error Reporting On/Off - '@' ................................................................. 4-11
4.4.14 Rate - 'J' ............................................................................................... 4-11
4.4.15 Zero Instrument - '01' ........................................................................... 4-11
4.4.16 Rate value - 'V' ..................................................................................... 4-11
4.4.17 Isolation Valve Open/Close - 'E' ......................................................... 4-11
4.4.18 Open Isolation valve - 'F' ..................................................................... 4-12
4.4.19 Tare value - 'B' ..................................................................................... 4-12
4.4.20 Tare On/Off - 'T' ................................................................................... 4-12
4.5 Output Code Format ....................................................................................... 4-13
Parameter Definitions .......................................................................... 4-14
Error Status Code ................................................................................ 4-18
4.6 RS232 Specific ................................................................................................ 4-19
4.6.1 Operation Using RS232 ....................................................................... 4-19
Direct mode ................................................................................. 4-20
Printer Mode ............................................................................... 4-21
Addressed Mode ......................................................................... 4-21
4.6.2 RS232 Output Code Format ................................................................ 4-24
4.7 Operation Using IEEE 488 .............................................................................. 4-26
4.7.1 Serial Poll ............................................................................................. 4-27
4.7.2 Standard IEEE Commands .................................................................. 4-27
4.7.3 IEEE Bus Time-out .............................................................................. 4-27
4.7.4 RS232 Command Specific Commands ............................................... 4-28
4.7.5 DPI 500 Mode ...................................................................................... 4-28
4.7.6 ASCII Values ........................................................................................ 4-29
Section Page

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vii
Contents
5 CALIBRATION ................................................................................................ 5-1
5.1 Calibration Check ............................................................................................ 5-1
5.2 Calibration Adjustment .................................................................................... 5-2
5.2.1 General Procedures ............................................................................. 5-3
5.3 Using the Calibration Menu ............................................................................. 5-4
5.3.1 Test ...................................................................................................... 5-4
5.3.2 Calibration (Cal) ................................................................................... 5-5
5.4 Checking Linearity Calibration ........................................................................ 5-6
5.5 Full Scale and Zero Adjustment ...................................................................... 5-7
5.6 Non-Linearity Adjustment ................................................................................ 5-8
6 MAINTENANCE .............................................................................................. 6-1
6.1 Safety Instructions ........................................................................................... 6-1
6.2 Fuse Replacement .......................................................................................... 6-2
6.3 Replace Vent, Source and Outlet Manifold Filters .......................................... 6-4
6.4 Cleaning .......................................................................................................... 6-4
6.5 Fault Finding ................................................................................................... 6-4
6.5.1 Error Codes .......................................................................................... 6-5
6.5.2 Controller Fault .................................................................................... 6-6
6.6 Approved Service Agents ................................................................................ 6-7
Section Page

K163 Issue No. 3
viii

K163 Issue No.3
1: Introduction 1-1
1
1 INTRODUCTION
Description
The DPI 520 is a programmable pneumatic pressure controller intended for
applications in automatic pressure testing and calibration.
A rugged Druck piezo resistive transducer measures pressure and is compen-
sated to standard or enhanced accuracy as required.
Dual loop control provides extremely accurate and repeatable setting of pressure
output.
The Druck pneumatic control actuator achieves this level of control whilst also
providing fast response and very low gas supply consumption.
Only 2U of 19 inch rack is required to house the unit which is controlled remotely
by a host computer for fully automatic applications or from one of the range of
Remote User Interfaces for manual or semi-automatic applications
Pressure demands via a digital interface are converted by the controller into a
regulated pressure supplied from a line or bottle source. Both RS232 and IEEE 488
interfaces are provided as standard. The controller module has both control and
measure modes. Up to three controllers may be ‘stacked’ and controlled from a
single User Interface or computer.
Two levels of accuracy enhancement are available as Options A1 and A2.
Option B provides negative pressure calibration.
The controller is interchangeable with a DPI 510 at IEEE and RS232
communications level. Essentially the DPI 520 is compatible with the Druck control
software products InteCal and ACS.
A remote User Interface (RUI 100 and RUI 101) is available giving manual control
and display on one, two or three DPI 520 in a 'stacked' system. In this way, control
is provided to a high accuracy over a wide pressure range. See the RUI 100/101
Product Note for details.

K163 Issue No. 3
1-2 DPI 520 User Manual
1.1 Instrument Specification
Pressure Ranges
Output Pressure
............................................................................................. 0 to 70 bar absolute
............................................................................................... -1 to 70 bar gauge
maximum 2 bar line pressure on gauge units
Maximum Safe Working Pressure
.....................................................................................125 % full scale pressure
Source Pressure Range
Positive pressure ............................................................. 105 to 115 % full scale
Negative pressure ............................................... Lowest pressure used less 5%
Accuracies
Assuming regular zeroing of the instrument, the following figures apply.
Combined non-linearity, hysteresis and repeatability
Standard Instrument ................................................................ ± 0.05% full scale
Option A1 .................................................................. Refer to Options, Page 1-5
Option A2 .................................................................. Refer to Options, Page 1-5
Temperature Coefficient
The temperature coefficient averaged over 10° to 30°C.
Standard Instrument ......................................................... ± 0.01 % Reading/°C.
Options A1 and A2 .................................................... Refer to Options, Page 1-5
Stability
NOTE: The following figure indicates 90 day stability and assumes
regular use of the zero facility.
............................................................................................. ± 0.015% of reading
Negative Pressures - Option B
Specification as per positive pressure but calculated as a percentage of the
positive full scale.
Controller Performance
Controller Stability ............................................................ ± 40 ppm of Full Scale
Fill Rate ............................................................ Dependant upon system volume

K163 Issue No.3
1: Introduction 1-3
1
Electrical Specification
Power Supplies
A.C. Supply Voltage ............................................................................88 to 264 V
Supply Frequency ...............................................................................47 to 65 Hz
Power .......................................................................................................... 60 VA
Communications Interfaces
The controller provides two digital communications channels, an RS232 and an
IEEE 488 channel. Three RS232 connections are provided but all of these access
a single processor port.
Analogue Output
Type ...................................................... Single ended D.C. voltage, representing
controller output pressure, referenced to instrument ground.
Bandwidth .................................................................................. 2000 Hz to -6 dB
Ranges
Fixed, to order with full scale output in one of the following ranges:
........................................................................ 0 to 2V; 0 to 4V; 0 to 5V; 0 to 10V
Accuracy .....................................................................................± 0.3% full scale
Temperature Error Band .................................................. ±0.5% F.S., 0° to 40°C.
Source Impedance .................................................................................. < 1000Ω
Input/Output Connections and Controls (Rear Panel)
Pneumatic Connections
Source, Vent and Outlet .................................................................. G1/8 (female)
Reference ..........................................................................................M5 (female)
Electrical Connections
Analogue Output ....................................... BNC connector - centre +ve, shell -ve
Host (RS232) ............................. 9-pin, D-type connector, wired for point to point
RS232 on pins 2 and 3
User Interface (RS232) ....................................................9-pin, D-type connector
for connection to Druck rack mounting Remote User
Interface. Daisy chained to RS232 port. Supplies 24V
D.C. supply for Remote User Interface.
IEEE 488 .......................................................................... Standard GPIB socket.
A.C. Power ....................................... IEC 320 connector. Line (L) and Neutral (N),
individually fused within socket.

K163 Issue No. 3
1-4 DPI 520 User Manual
Electrical Controls
Stacking Switch..................................... Controls use of RS232 interface.
Calibration ............................................. Switch (located under calibration label),
used only during instrument calibration.
Input/Output Connections (Front Panel)
Electrical Connections
User Interface (RS232) ......................................................... 6-way Lemo socket
for connection to Druck Desktop Remote User Interface, Type RUI 100.
Daisy chained to RS232 port with automatic bypass when not in use. Supplies
24V d.c. for the user interface.
Environmental Specification
Temperature
Operating ......................................................................................... 0° to +40°C
Operating (compensated) ............................................................ +10° to +30°C
Storage ......................................................................................... -20° to +60°C
Protection
Front panel ................................................................................................to IP40
EMC
Meets: ........................................................................... EN 50081-1 (emissions)
....................................................................................... EN 50082-1 (immunity)
Safety
Meets: .............................................................................................. EN 61010-1
Pressure Media
.......................................................................................................clean, dry gas
Weight
................................................................................................................... 5.2 kg
Dimensions
............................................ 90 mm (high), 482 mm (wide) and 360 mm (deep)*
*Indicates case depth. Add 40 mm for the depth of handles.

K163 Issue No.3
1: Introduction 1-5
1
Options
Option A1
Combined non-linearity, hysteresis and repeatability
........................................................ ±0.05% of reading (20% to 100% full scale)
............................................................. ±0.01% of full scale (0 to 20% full scale)
Temperature Coefficient
.....................................................±0.002% rdg/°C (averaged over 10° to 30°C)
Option A2
Combined non-linearity, hysteresis and repeatability
...................................................... ±0.025% of reading (20% to 100% full scale)
........................................................... ±0.005% of full scale (0 to 20% full scale)
Temperature Coefficient
.....................................................±0.002% rdg/°C (averaged over 10° to 30°C)
Option B
Negative Calibration
Error as a percentage of +ve full scale. Value depending on the accuracy option
chosen.
Accessories
The instrument is despatched with the following items:
User Manual (K163)
Calibration Certificates
Power Supply Lead

K163 Issue No. 3
1-6 DPI 520 User Manual
1.2 APPLICATIONS
1.2.1 Control by Remote Computer via IEEE 488
Using the IEEE 488 general purpose control bus, a remote computer can control
either a single stand alone unit or a number of units up to a maximum of 15. When
controlling a number of instruments each instrument on the bus is allocated a
unique address (set with the instrument via a SETUP facility). Each instrument is
first addressed and then instructed by means of control codes to carry out the
required functions (e.g.) mode change, output pressure change, rate change or
send current output pressure.
A special application of this mode of control allows the output pressure ports of a
number of controllers to be connected together into a common manifold. By using
instruments with different control pressure ranges, this permits a wide range of
accurately controlled pressures to be applied to a common manifold.
Figure 1.1 shows the general arrangement. Section 3 contains details for the
installation of this configuration of instruments.
Figure 1.1 - Control by Remote Computer via IEEE 488

K163 Issue No.3
1: Introduction 1-7
1
1.2.2 Control by Remote Computer via RS232
●●
●●
●PC to Instrument
A single instrument is connected directly to a computer and communications
can be controlled either by full hardware handshaking or software handshaking.
Section 3, Installation, details the connection method for both options.
●●
●●
●Instrument to Printer
A stand alone instrument can be connected to a non-intelligent terminal or a
printer. In this mode the instrument provides a continuous flow of data, on a
timed basis. Interconnection details are the same as for the connection of a
control computer and are given in Section 3.
1.2.3 Control via Remote User Interface
Two types of Druck Remote User Interface can be used to control up to three DPI
520 instruments. These remote interface units, types RUI 100 (desk top) and RUI
101 (rack mounted), plug into special user interface sockets, located on the front
and rear panels respectively.
The Remote User Interface is automatically powered as soon as it is plugged into
a controller.
The RUI assumes that the controllers have a common pressure output. Using
instruments with different pressure ranges permits a wide range of accurately
controlled pressures to be applied to a single outlet.
Figure 1.2 shows the general arrangement. Refer to K181 for details of RUI 100/
101 connections.

K163 Issue No. 3
1-8 DPI 520 User Manual
Figure 1.2 - Control from a Remote User Interface

K163 Issue No. 3
2: Functional Description 2-1
2
2 FUNCTIONAL DESCRIPTION
2.1 General
The DPI 520 instrument is a single channel pressure controller, designed to be
programmed either from an external computer system or remote user interface.
No user controls are provided on the instrument, it’s local keyboard being used only
for set-up, calibration and maintenance operations. The use of these functions are
described in Sections 4 and 5 respectively.
Digital programming of the instrument is effected via a RS232 serial interface or
via an IEEE 488 parallel interface. The instrument can be configured in a number
of different ways as detailed in Section 1. Section 3 details the installation
procedures.
2.2 Instrument Electronics
2.2.1 Digital Electronics (Fig 2.1)
The instrument draws it’s power supplies from an internal power supply unit which
is, in turn, powered from an external a.c. source.
An internal microprocessor system controls the RS232 and IEEE 488
communications channels. One RS232 port is provided and one IEEE 488
channel. The RS232 port has three inputs, one of which is used for host
communications. The other two are used for the connection of either the Druck
RUI 101 (rack mounted) or the RUI 100 (desktop) Remote User Interfaces.
Although there are three RS232 connectors on each instrument, (one RS232 and
two User Interfaces), effectively they access only a single RS232 processor port.
A switching network has auto detection of the presence of a Remote User Interface
(RUI), plugged into one or other of the RUI sockets.

K163 Issue No. 3
2-2 DPI 520 User Manual
Figure 2.1 - Digital Electronics, Functional diagram
The microprocessor system also controls the flow of data to the instrument’s
display. The display is a two line (20 characters/line) liquid crystal dot matrix type.
Operationally, it is used to display pressures, functions and messages.
A keyboard, linked to the microprocessor, provides a user interface for set-up and
calibration purposes only. It is not used for normal operation, all operational
commands being sent via one of the two communications interfaces.
Control of the Analogue to Digital (A-D) Converters used in the analogue and valve
control circuits is effected via the microprocessor system’s bi- directional control
bus. A simplified description of the analogue control channel follows.

K163 Issue No. 3
2: Functional Description 2-3
2
2.2.2 Analogue Circuit Operation (Fig 2.2)
Output pressure control is effected by means two solenoid operated valves. One
of these valves, the Apply valve, controls the application of a source pressure to
the output manifold. The other valve, the Release valve, releases the output
pressure. The output pressure is controlled by modulating the drive to each of
these valves, controlling their relative on/off times. An Isolation valve, also
controlled by the microprocessor, is used to isolate the controller from the external
pneumatic system. The controller output pressure (external system pressure
when the isolation valve is open), is measured by a suitably scaled, internally
mounted, pressure transducer.
Pressure demands to the controller are sent via either the RS232 or IEEE 488
communications interface and decoded by the microprocessor. The decoded
demand is sent to the setpoint A-D converter, processed (with other loop control
terms) and applied to an error amplifier. The other input to the error amplifier is the
transducer output signal, (representing the actual pressure at the controller
output).
The error amplifier produces a bipolar error signal proportional to the magnitude
and direction of the error between the setpoint demand and the actual output of the
controller. This error is first processed by an error signal processing circuit, under
the control of the microprocessor, to drive a pulse width modulator. The output of
the pulse width modulator drives the Apply and Release valves to change the
output pressure in an appropriate direction to correct the error i.e. to equalise the
setpoint demand and pressure feedback signals. A temperature feedback signal
from the output manifold, modifies the drive to the output valves should they
become overheated.
An analogue signal, proportional to the output pressure, is derived from the output
of the pressure sensing transducer. The output of the pressure transducer is
scaled by an amplifier/buffer and filtered before outputting from the instrument as
a d.c. signal. The gain of the output amplifier is set during manufacture to provide
one of four scaled ranges (refer to Section 1 - Specification).

K163 Issue No. 3
2-4 DPI 520 User Manual
Figure 2.2 - Analogue Electronics, Functional Diagram