GE RPT 301 User Manual

GE

Sensing

RPT 301

Digital Output Pressure Transducer

User Manual K177

© General Electric Company. All rights reserved.

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

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RPT 301 User Manual i

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:

The following symbols are used in this manual

Abbreviations are the same in the singular and plural.

EMC electromagnetic compatibility
FS full-scale
IEC International Electrical Council
inHg inch of mercury

2

kg/cm
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

kilogram per centimetre squared

Hazard, a warning highlighting a danger that would result in
injury. Also a marking on the instrument referring the user to
this publication.

CE

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This symbol, on the instrument or in the manual, indicates a
static sensitive component.

This product meets the essential protection requirements of
the relevant EEC directives. Further details of applied stand­ards may be found in the product specification.

RPT 301 User Manual iii

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:

Temperature affects: ............... ±0.02% FS over operating temperature range

Long term stability:

Ranges

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

Standard ................................................................. ± 0.02% FS

Option A .................................................................. ±0.01% FS

Standard ............................................. 150 ppm per 12 months

Option A ............................................. 100 ppm per 12 months

.................................................................. 750 to 1150 mbar a

.................................................................... 35 to 1300 mbar a

.................................................................... 35 to 2620 mbar a

.................................................................... 35 to 3500 mbar a

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Power supply

Electrical Safety: .......................................... EN61010 (IEC 1010) as applicable

Electromagnetic compatibility

Switch on

Pressure measurement

Measurement cycle: ........................................ Fixed, nominally 0.5 seconds

Reading Filter:

Reading Resolution: ........................ Programmable number of decimal places

Data Communications:

Power Control

(Remote Start-Up) A floating ‘volt free’ two-wire control input is provided

Pressure connection

Pressure medium compatibility: .......................

Voltage .............................................................. 4.5 to 32 V DC

Power .......................... 0.6 Watts at 5 V to 0.75 Watts at 32 V

............................................................ EN50081-1 (emissions)

............................................................. EN50082-2 (immunity)

Settling Time: ... Less than 5 seconds (with filtering disabled)

Single pole low pass filter, variable time constant and step response

Serial RS232 or RS485 (selectable)

Software or hardware handshaking on RS232

software handshaking only on RS485.

to enable the instrument to be remotely switched on
or off.

.............................................................................. G1/8 female

overpressure ................................... 1.25 x calibrated full-scale

pressure containment ................................................... 5 bar a

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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4 RPT 301 User Manual

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.

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.

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RPT 301 User Manual 5

Figure 2-2 Instrument Dimensions

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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

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.

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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

RPT 301 User Manual 7

see te

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

current limiting resistor
for high supply voltages

xt

Connections for continuous operation

7

4

Connections for remote on/off control using RS232 output

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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.

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RS485
interface lead to PL3
LK2 to position B

RPT 301 User Manual 9

LK2

LK1

B

A

B

PL3

Figure 2-3 Changing the communication interface

PL1

B

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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.

computer

screened cable

RPT
301

connect screen
to connector shell

Screening to ensure EMC performance

enclosure

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RPT 301 User Manual 11

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

Command Function

Measurement

R

<CR>

G

A

X

Set-up

U

F

B Set reading resolution

O

SStatus

I

User calibration

C

P Change protection PIN

CR CRLF

Command Terminators

Return stored reading

Return stored reading

*

Get New Reading

Auto send reading

Auto send from power-up

Set units

Set filter

Set communication parameters

Identity

User calibration (linearity)

* Short form of the 'R<CR>' command

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RPT 301 User Manual 13

3.3 General Command Format

The instrument is controlled by a sequence of single letter commands.
Some commands require one or more numeric values to follow the
letter, the correct number of parameters must be sent with this type of
command. All command fields must be separated by a comma. The
instrument accepts upper-case or lower-case letters.

Single commands

Single commands should be of the form:

Command, P1, P2, ,Pn<CT>

Where, Command is a single ASCII character, P1 to Pn are numbers in
the form: (-) mmm.ddd

or

Example:

Single Command

<CT> is the command terminator (CR or CRLF)

A,3<CR> selects auto-send mode with 3 second period

a,3<CRLF> has the same effect

Command Strings

Commands can be strung together with a separating semicolon. The
whole command string is only interpreted and actioned when a valid
terminator is received.

Example:

Multiple Commands (Command String)

1. O, PIN, address, baud, data bits, stop bits, parity, handshake; U, units;
P, PIN, New PIN

(-)m.ddddE(-)xx

e.g. 123.456 or 1.23456E02

Reply: None

This command string sets: port address (00), baud rate, units and new PIN

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14 RPT 301 User Manual

2. U, O; G; R; G; R; U, 16; G; R; G; R; G; R; A, 100

Reply: Reading 1 mbar

Reading 2 mbar

Reading 3 psi

Reading 4 psi

Reading 5 psi

Then at 100 second intervals - Reading psi

This command string sets the instrument units to mbar, returns two
consecutive readings, changes units to psi, returns three consecutive
readings and then selects auto-send mode with a period of 100 seconds
between readings.

Command String Limitations

Auto-send mode and diagnostics mode are cancelled when a further
command is received, this should be used at the end of a command
string.

Note: The C, L and T commands are interactive and are not

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suitable for multiple commands.

RPT 301 User Manual 15

3.4 General Reply Format

For commands that have a reply string, the reply terminator <RT> is
always transmitted and is always <CR> followed by <LF>.

<RT> is expected with all commands but only shown in some of the
following sections for clarity (e.g.: Section 5.3 Diagnostics Mode).

Command Terminator

Command strings must end with the command terminator <CT>.

For Dumb Terminal applications press the carriage return (or enter)
key.

With a Terminal Emulator communications application, the
application must be set-up to give the required output when the carriage
return (or enter) key is pressed.

For Custom applications, <CR> (decimal 13) or <CRLF> (decimal 13
followed by decimal 10) must be added to the end of each complete
command string.

<CT> is expected with all commands except for some interactive
commands where further explanation is necessary (e.g.: Section 4 User
Calibration).

3.5 Error Message

Error messages are generated from two sources:

a. The command decoder. A command error causes the return

of an error message and stops the rest of the command string.
The instrument sends an error message corresponding to the
command error.

b. A pressure sensor fault causes an error message to be sent.

Serious faults block the transmission of pressure data and
sends the error message in place of data.

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Error Message Format

The form of the error message:

ERROR nn - where nn is a decimal number

Defined error numbers are:

01 - Bad command

02 - Bad password

04 - Bad data detected by checksum

08 - Data out of range

16 - Hardware fault

32 - Pressure outside range

64 - System not ready

Error messages are sent when an error is detected.

Example

When first detected the hardware fault error is sent once even though
the fault persists, sending the S (status) command provides further
details of the fault.

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3.6 Detailed Command Definitions

Measurement Commands

R - Return stored reading

This command retrieves the current stored reading, as the reading is the
stored and filtered (if the filter is selected) there will be no delay in the
reply.

Command: R

Reply: nnnnnnn<SP>UNITS

Where:

‘nnnnnnn’ is the stored reading as a floating point
number ‘Units’ are the units for nnnnnnn (i.e. mbar,
mH2O, psi etc.)

G - Get reading

This command initiates a new measuring cycle. The reading is not
returned by this command, string ‘G’ and ‘R’ together to return the
reading (i.e. G;R<CR>). The instrument proceeds to the next command
after the end of the measurement cycle (see specification for duration)
or in the event of a reading failure (fault condition) after a time-out of
approximately 2 seconds. The command synchronises the measurement
cycle with an external event.

Note: Use of the G command overrides any filter that has been

Command: G

A - Auto send reading

This command places the instrument into a mode where the value
currently held in the reading store is sent to the control computer with
a specified interval between each transmission. Auto send is terminated
by any following command.

selected. The reading obtained is passed without filtering

to the reading store.

Reply: None

Result: Initiates new measurement cycle

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Command: A,nnnnnn

Where: ‘nnnnnn’ is a number between 1 and 999999. This is

the period in seconds between successive
transmissions.

Reply: None

Result: A reading is transmitted every nnnnnn seconds.

The transmission format is the same as the reply of the
‘R’ command.

X - Auto Send from switch-on

The ‘A’ command is cancelled by any following commands and is not
restored at switch-on. If the pressure transducer continuously sends
readings and does so even after power failure, (this includes using the
‘shutdown’ facility) then the ‘X’ command can be used to select this
facility. This command allows a transmission period to be stored in
nonvolatile memory which will be automatically loaded and actioned as
if the ‘A’ command had been sent at switch-on.

Command: X,nnnnnn

Where: ‘nnnnnn’ is a number between 0 and 999999.

This is the transmission interval in seconds as for the
‘A’ command. A value of 0 disables the Auto send at
switch-on.

Reply: None

Result: Instrument powers up in auto-send mode with the

selected transmission interval.

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RPT 301 User Manual 19

Set-up Commands

U - Unit Set-up

This command sets the units of the pressure measurement; the
selection is nonvolatile.

Command: U,nn

Where: ‘nn’ can be up to two digit number taking one of the

following values:

* 0 - mbar 13 - mH20

1 - Pa 14 - torr

2 - kPa 15 - atm

3 - MPa 16 - psi

4 - hPa 17 - lb/ft

5 - bar 18 - inHg

6 - kg/cm

7 - kg/m

2

2

19 - inH2O04

20 - ftH2O04

8 - mmHg *21 - mbar

9 - cmHg 22 - inH2O20

10 - mHg 23 - ftH2O20

11 - mmH2O *24 - mbar

12 - cmH2O

2

* Note: mbar can be selected using code 0, 21 or 24.

Reply: None

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F - Filter Set-up

This command sets the instrument reading filter coefficients.

Command: F, step, average

Where: step is a pressure band within which the filter operates.

If the pressure steps outside this band, the filter is
bypassed. This gives an unfiltered response to
non-noise step changes.
step takes a value expressed as a percentage (0 ­100%) of full-scale.
If step = 0 then the filter is disabled.
average is the number of sequential readings (1 -

99) averaged by the filter. High values effectively

Reply: None

B - Set Resolution

This command enables the decimal place of the reading to be adjusted
within the instrument’s resolution, see specification. The reading
resolution is automatically selected according to the instrument full­scale and the units that have been selected using the units set-up
command. An algorithm is used that gives a resolution which does not
interfere with the accuracy of measurement and is as noise-free as
possible before filtering. The set resolution command allows the
number of decimal places of the transmitted value to be specified, this
overrides the automatic selection of resolution for the current selected
units.
Changing units cancels any previous set resolution command.
The command is nonvolatile and remains selected until the units are
changed. Changing and restoring the units can be used to cancel the
set resolution command.
Command: B,n

Reply: None

Result: Sets the transmitted number of decimal places to be ‘n’ 0-5

max depends on units resolution.

give the filter a long time-constant.

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RPT 301 User Manual 21

O - Set Communications Options

This command sets the communication port parameters to match those
of the control computer.

Note: When changing these settings care must be taken to avoid losing

communication with the instrument. If this should happen the default
communications settings can be restored (those operational at the time
of shipment) by moving Link 1 to the ‘A’ (Restore) position and
switching the power off and back on. The link should then be moved
back to the ‘B’ (Normal) position. If the link is left in the ‘A’ (Restore)
position it is not possible to permanently change the communications
settings; this may be considered useful in some applications. Default
on shipment is set to the command O, 000,00,0,0,0,0,0 which means:
9600 baud, 8 data bits, 2 stop bits, no parity, no handshake.

Command: O, PIN, address, baud, data bits, stop bits,

Where: PIN is a three-character password = 000 - 999

Reply: None

parity, handshake

address always = 00

baud rate value = 0 - 7: 0 = 9600, 1 = 4800, 2 = 2400, 3 = 1200,

4 = 600, 5 = 300, 6 = 150, 7 = 75

data bits: 0 for 8 data bits1 for 7 data bits

stop bits: 0 for 2 stop bits 1 for 1 stop bit

parity: 0 = no parity 1 = even parity 2 = odd parity

handshake: 0 = no handshake

1 = software handshake (XON/XOFF)

2 = hardware handshake (RTS/CTS)

Note: When RS485 hardware has been selected the serial link is configured as

full duplex with no hardware handshaking. Handshake = 2 is not valid
for RS485 hardware.

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S - Status

This command returns the instrument status.

Command: S

Reply: STATUS nn

Where nn: 01 = Frequency outside limits

Result: no change

I - Identity

This command requests the unit to send items of data which describe
the unit identity.

Command: I

Reply: type, range, S/N, cal date

Result: No change in status or operation

Where: Type = Equipment model (Druck RPT 301)

Command: I,S/PIN, Name Value<CR> format

i. When Name = S, Value = nnnn/yy-mm

ii. When Name = H, Value = nnnn

iii. When Name = L, Value = nnnn

02 = Diode voltage outside limits
04 = Electronics failure

Combination errors: a status 06 represents diode

voltage and electronics failure.

Range = Pressure range, lower and upper and

pressure type
S/N = Transducer serial number
Cal date = Date of last calibration

Reply: S/N = nnn/yy-mm
Result: sets displayed serial number

Reply: HIGH RANGE = nnn mbar
Result: sets displayed highest operating pressure (mbar)

Reply: LOWEST RANGE = nnn mbar
Result: sets displayed lowest operating pressure (mbar)

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RPT 301 User Manual 23

4 Calibration

The instrument is supplied with a calibration certificate. For the
instrument to stay accurate it is recommended that it is checked every
12 months.

 The use of a Class A compensated deadweight pressure standard is

recommended.

 The following procedures should be carried out in a controlled

environment by qualified personnel.

 If the accuracy of the instrument is not within the specification, carry out

a calibration adjustment procedure.

 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.

 The manufacturer offers a comprehensive and, if required,

NAMAS accredited calibration service.

 Calibration Check

A calibration check should be carried out at chosen intervals. The
readings of the instrument should be compared with a pressure standard
and, after any adjustments for accuracy (traced to National Standards),
the differences recorded. The adjusted differences can then be
compared with the required accuracy for the instrument. If necessary
a calibration adjustment can be carried out.
The recommended procedure is to check at increasing and then
decreasing intervals of 0, 20, 40, 60, 80 and 100% of full-scale.

C - User Calibration (Linearity/Drift Compensation)

This command performs a `best straight line fit' to the remaining errors
of the transducer or does a single pressure point correction. Entering
one pressure point causes the offset between the transducer and the
pressure standard to be added/subtracted across the whole pressure
range. Entering two pressure points (near zero and near full-scale)
cancels zero and full-scale drift. Entering more pressure points reduces
the remaining non-linearity and makes the zero and full-scale correction
more accurate.

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24 RPT 301 User Manual

The calibration routine requires a minimum of two pressures within the
operating extremes (maximum of six pressures). The instrument
software calculates an offset and gain correction to be applied to all
subsequent readings using a statistical best straight line method.

For single point calibration, the gain factor is set to unity.

Notes

1 For the pressure sensor to rapidly respond to the applied pressure,

disable the filter by sending the filter command F, 0,0<CR>.

2 Before sending the ‘C’ command set the instrument to operate in the

pressure measurement units required for calibration. i.e. U, 0<CR>
selects mbar. Always use the same units when entering applied
pressures.

Command: C, PIN

Reply: APPLY PRESSURE nn

Reply: ENTER APPLIED PRESSURE nn

<CT>
Reply: MORE? (Y/N)

Reply (if N): SLOPE XX INTERSECT YY

Reply (if N): CALIBRATION TERMINATED

Reply (if Y): ENTER CAL DATE

Reply: CALIBRATION COMPLETE

apply pressure, when steady send <CT>

type pressure value - decimal number followed by

type Y <CT> to calibrate more points

or

type N <CT> to complete calibration point entry

ACCEPT CALIBRATION (Y/N)
type Y <CT>
to accept and permanently update the calibration

or

type N <CT> to terminate without saving

end of calibration procedure

type date in the format DD/MM/YY

Where:nn = pressure point 1-6

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RPT 301 User Manual 25

P - Change PIN

This command changes the PIN (Personal Identification Number) that
protects the calibration data. The instrument is shipped with the PIN

000. If the PIN is lost, the default (000) may be restored by fitting the
‘default’ link and switching off and then on.

Note: Restoring the defaults restores ALL of the factory settings including the

communication parameters.

Command: P, PIN, New PIN

Where: PIN is the existing 3-digit code (000 to 999) and New

Reply: None

Result: PIN is replaced by New PIN

PIN is the replacement PIN.

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5 Maintenance

5.1 General

User maintenance on this instrument is limited to checking the LED
indicator, a diagnostic mode and cleaning the case.

5.2 LED Indicator

With the lid of the instrument removed, an LED located on the PCB
flashes when a pressure conversion is carried out. This indicates that
the instrument has power, that the processor is functioning and the
transducer frequency and diode voltage are within normal limits.

5.3 Diagnostic Mode

D - Diagnostic Mode

This command places the instrument into the diagnostic mode.

Command: D, mode

Where: mode is a single digit:

1 Dump all 512 stored values.
2 Dump transducer coefficients (checks LOAD L command).
3 Dump calibration factors i.e. gain, offset etc.
4 Continuous output of sensor diode voltage (temperature) mV.
5 Continuous output of sensor frequency in Hz.

Result: The reply depends on the mode as follows:

Mode 1

32 lines of output as follows:

aaa -

nn nn nn nn nn nn nn nn nn nn nn nn nn nn nn nn<RT>

where: aaa = hexadecimal address offset (0 to 1FFH) and

nn = hexadecimal data

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RPT 301 User Manual 27

Mode 2

“K00”,Coeff 1<RT>...”K55",Coeff 25<RT>,

”KX”,Coeff X<RT>,

”KY”,Coeff Y<RT>,

“CS”,RPT barometric checksum<RT>,

“SN”,RPT serial number<RT>,

“RH”,RPT max. operating pressure (mbar)<RT>,

“LH”,RPT min. operating pressure (mbar)<RT>,

“TYPE”,RPT type<RT>

Mode 3

Frequency constant, pressure gain, pressure offset, diode volts offset

Mode 4

DIODE = value - For every reading where value is the diode voltage in
mV

Mode 5

FREQUENCY = value - For every reading

Where: ‘value’ is the sensor frequency measured in Hz

* Modes 4 and 5 are cancelled by any other command.

5.4 Cleaning

Clean the external case of the instrument with a damp lint-free cloth and
mild detergent. Make sure that there is no debris in the pressure port.

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5.5 Approved Service Agents

Find approved agents for the servicing of Druck Instruments at:

www.gesensing.com

K177 Issue No. 3