GE Sensing RPT 301 User manual

RPT 301
Digital Output Pressure Transducer
User Manual K177
GE
Sensing

© General Electric Company. All rights reserved.

K177 Issue No. 3
RPT 301
Digital Output Pressure Transducer
User Manual
K177
© 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, nor stored in any Data Processing
System, without the express written authority of Druck Limited.

K177 Issue No. 3

RPT 301 User Manual i
K177 Issue No. 3
Safety
The manufacturer has designed this instrument to be safe when operated
using the procedures detailed in this manual. Do not use this instrument for
any other purpose than that stated. Do not apply values greater than the
maximum value stated.
This manual contains operating and safety instructions that must be
followed for safe operation and to maintain the instrument in a safe
condition. The safety instructions are either warnings or cautions issued to
protect the user and the equipment from injury or damage. Use qualified*
technicians and good engineering practice for all procedures in this manual.
Pressure
Do not apply pressure greater the maximum safe working pressure to the
instrument.
Electrical Safety
This instrument is designed to be safe when using options and accessories
supplied by the manufacturer.
Toxic Materials
There are no known toxic materials used in this instrument.
Maintenance
The instrument must be maintained using the manufacturer’s procedures
and should be carried out by authorised service agents or the manufacturer’s
service departments.
Technical Advice
For technical advice contact the manufacturer or subsidiary refer to section
5.5.
*A qualified technician must have the necessary technical knowledge,
documentation, special test equipment and tools to carry out the required
work on this instrument.

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ii RPT 301 User Manual
Abbreviations and Symbols
The following abbreviations are used in this manual.
Note: Abbreviations are the same in the singular and plural.
EMC electromagnetic compatibility
FS full-scale
IEC International Electrical Council
inHg inch of mercury
kg/cm2kilogram per centimetre squared
kPa kilo Pascal
mA milli Ampere
mm milli metre
NL, H & R non-linearity, hysteresis and repeatability
PCB printed circuit board
psi pound per square inch
RPT resonant pressure transducer
V Volt
VA Volt amp
Hazard, a warning highlighting a danger that would result in
injury. Also a marking on the instrument referring the user to
this publication.
This product meets the essential protection requirements of
the relevant EEC directives. Further details of applied stand-
ards may be found in the product specification.
CE
The following symbols are used in this manual
This symbol, on the instrument or in the manual, indicates a
static sensitive component.

RPT 301 User Manual iii
K177 Issue No. 3
Table of Contents
1 Introduction ................................... 1
1.1 Description ................................................ 1
1.2 Specification .............................................. 1
2 Installation ..................................... 4
2.1 Mounting the Transducer ......................... 4
2.2 Pressure Connection ................................ 4
2.3 Electrical Connection ................................ 6
3 Operation ....................................... 11
3.1 System Operation ..................................... 11
3.2 Command Summary ................................. 11
3.3 General Command Format ....................... 13
3.4 General Reply Format ............................... 15
3.5 Error Message .......................................... 15
3.6 Detailed Command Definitions ................ 17
4 Calibration ..................................... 23
5 Maintenance .................................. 26
5.1 General ...................................................... 26
5.2 LED Indicator ............................................ 26
5.3 Diagnostic Mode ....................................... 26
5.4 Cleaning .................................................... 27
5.5 Approved Service Agents ......................... 28

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iv RPT 301 User Manual

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RPT 301 User Manual 1
1 Introduction
1.1 Description
The RPT 301 Digital Output Pressure Transducer measures air pressure
applied to the connection port and produces an electrical output. It
comprises a resonant sensor connected to a printed circuit board to
produce a serial digital output and is contained in a metal enclosure to
IP65 standard. The instrument is designed to communicate with
compatible equipment using a serial communications system which
can be selected by the user for either RS232 or RS485 standard
communications interface. The power supply for the instrument is a
wide tolerance DC voltage with a low power consumption A remote
start-up facility enables the instrument to be remotely switched on and
off to save power.
1.2 Specification
Accuracy
Non-linearity, hysteresis and repeatability:
Standard ................................................................. ± 0.02% FS
Option A .................................................................. ±0.01% FS
Temperature affects: ............... ±0.02% FS over operating temperature range
Long term stability:
Standard ............................................. 150 ppm per 12 months
Option A ............................................. 100 ppm per 12 months
Ranges
.................................................................. 750 to 1150 mbar a
.................................................................... 35 to 1300 mbar a
.................................................................... 35 to 2620 mbar a
.................................................................... 35 to 3500 mbar a
Dimensions
Weight: ...................................................................................... 0.65 kg
Size: ...................................................... 125 mm x 80 mm x 57 mm
Environment
Operating temperature range ..................................................... -20 to + 60C
Storage temperature range ......................................................... -40 to + 80C
Sealing: ........................................................................................... IP65

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Power supply
Electrical Safety: .......................................... EN61010 (IEC 1010) as applicable
Voltage .............................................................. 4.5 to 32 V DC
Power .......................... 0.6 Watts at 5 V to 0.75 Watts at 32 V
Electromagnetic compatibility
............................................................ EN50081-1 (emissions)
............................................................. EN50082-2 (immunity)
Switch on
Settling Time: ... Less than 5 seconds (with filtering disabled)
Pressure measurement
Measurement cycle: ........................................ Fixed, nominally 0.5 seconds
Reading Filter:
Single pole low pass filter, variable time constant and step response
Reading Resolution: ........................ Programmable number of decimal places
Data Communications:
Serial RS232 or RS485 (selectable)
Software or hardware handshaking on RS232
software handshaking only on RS485.
Power Control
(Remote Start-Up) A floating ‘volt free’ two-wire control input is provided
to enable the instrument to be remotely switched on
or off.
Pressure connection
.............................................................................. G1/8 female
overpressure ................................... 1.25 x calibrated full-scale
pressure containment ................................................... 5 bar a
Pressure medium compatibility: .......................
Dry gases compatible with:
Glass, Silicon, Titanium, Stainless Steel and Epoxy adhesive
Note: Continuing development sometimes necessitates specification changes
without notice.

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RPT 301 User Manual 3
Accessories
The following items are delivered with the instrument after manufacture.
User manual K177 (this publication)
Calibration certificate
Mating electrical connector (if ordered)

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Figure 2-1 Mounting Arrangement
2.2 Pressure Connection
The pressure port is a G1/8. If a pipe is connected to this port a bonded
seal must be used. The instrument is very sensitive to air movement
(small local pressure changes), when the pressure port is directly
sensing the atmosphere, the fitting of a filter or restrictor is
recommended.
2 Installation
Installation must be carried out by a qualified technician.
2.1 Mounting the Instrument (Figure 2.1)
The instrument can be mounted on a vertical surface using two screws
or bolts to a maximum diameter of 4 mm.

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RPT 301 User Manual 5
Figure 2-2 Instrument Dimensions

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Power supply
The instrument is internally fused with reverse polarity and overvoltage protection.
Note: The power input is transformer isolated from the logic circuits and the
serial data link. The isolation voltage is 50V dc.
For continuous operation the ‘Start-up’ connections should be connected to the
supply, make sure the polarity is correct and the current requirements are met.
When RS232 is used, the RTS line can be connected to the `Start-up' input and
the RTS input on pin D so that the control computer can turn on the instrument.
2.3 Electrical Connection
The electrical connector is a 10-way connector (MIL C26482) for serial,
parallel and power connections.
Instrument Connector - Plug, Amphenol 62GB 12E12 - 10P
Cable Connector - Socket, Amphenol 62GB 16F12 - 10S
Communication connections
When configured for:
RS485
A = Power Supply -ve
B = Power Supply +ve
C = Chassis
D = Data out +ve
E = Data out -ve
F = Data In +ve
G = Data In -ve
H = Data Ground
J = Start-Up -ve
K = Start-Up +ve
RS232
A = Power Supply -ve
B = Power Supply +ve
C = Chassis
D = RTS Input
E = Data Out
F = CTS Output
G = Data In
H = Data Ground
J = Start-Up -ve
K = Start-Up +ve

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RPT 301 User Manual 7
The start-up +ve and -ve connections must be connected for the
instrument to operate. There are many ways of connecting the
start-up facility for example:
Power control
The current consumed by the instrument is approximately 1 mA at 3 V, 2 mA at
5 V rising to 16 mA at 32 V. If necessary, when using a supply greater than 5
V, a series resistor can be used to reduce the current drain to 1 mA.
Connections for remote on/off control using RS232 output
current limiting resistor
for high supply voltages
see
t
e
xt
Connections for remote on/off control
Connections for continuous operation
7
4

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Communications
The installed instrument is controlled by the serial data interface.
Software or hardware handshaking can be used on the RS232 interface
and only software handshaking on the RS485 interface.
Changing the communication interface standard (Figure 2-3)
The communication interface standard is set at manufacture to RS232
but can be changed as follows:
Remove the lid of the instrument to gain access to the PCB.
CAUTION:
THE PCB CONTAINS SENSITIVE ELECTRONIC COMPONENTS.
Carefully connect the interface connector lead and the link LK2 in the
following positions:
RS232
interface lead to PL1
LK2 to position A
Refit and secure the lid of the instrument.
RS485
interface lead to PL3
LK2 to position B

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RPT 301 User Manual 9
Figure 2-3 Changing the communication interface
PL3
LK2
B
B
LK1
A
B
PL1

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connect screen
to connector shell
screened cable
computer
enclosure
RPT
301
Screening to ensure EMC performance
Screening
Make sure that the chassis connection between the control computer
and the instrument is continuous. Use screened cable and bond the
cable screening to the connector shell of the instrument and to the
computer enclosure.

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3 Operation
3.1 System Operation
The frequency output from the sensor is counted for a fixed number of
cycles. A mid-scale pressure gives a measurement period of
approximately 0.5 seconds. During this time a high frequency clock is
also being counted and at the end of the measuring cycle it is this value
which is transferred to the processor for conversion into its pressure
equivalent.
Measurement cycles are continuous, unless specifically interrupted
(see the G command). Each cycle delivers a new pressure value to the
programmable filter. The output of this filter is stored in a buffer and
may be requested by the control computer or sent automatically at a
programmable interval to the control computer.
3.2 Command Summary
The instrument has a range of commands summarised in the table and
detailed in this section. Some of these commands generate a reply
from the instrument, the general format of these replies is given in
section 3.4.

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Command Summary Table
* Short form of the 'R<CR>' command
Command Function
Measurement
RReturn stored reading
<CR> *Return stored reading
GGet New Reading
AAuto send reading
XAuto send from power-up
Set-up
USet units
FSet filter
B Set reading resolution
OSet communication parameters
SStatus
IIdentity
User calibration
CUser calibration (linearity)
P Change protection PIN
CR CRLF Command Terminators