Field Gauge API Document

Field Gauge API Document

The API document allows users to communicate with a Field Gauge Model LC10 or LC20 or with a Process Meter LC30

Compatible with all LC Gauges

using firmware 1.008 and above


PC Serial Port Settings

The recommended pc serial port settings are:

Baud – 9600

Parity – N

Data Bits – 8

Stop bit – 1

Flow Control – None

 

The LC Gauge will automatically detect the baud rate of the incoming data. Therefore, no settings need to be defined on the gauge for communications to work properly. Higher baud rates may be used if it is determined by the end user that communications will remain reliable.

 

 

Serial Command Summary

The command is followed by a space character, then the parameter. These command/parameters are expected to be followed by either a carriage return (\r or 0x0D) or a line feed (\n or 0x0A) character.  Channels are 1, 2, 3 (CH2-CH1), or 4 (CH1-CH2).

Command

Description

Parameters

Default Setting

AUTOPWR

Auto Power Down the Gauge

0 (Never) to 255 minutes

NEVER

AUTOPWR?

Query Auto Power Down Setting

 

 

BATT?

Queries Battery Status

None

 

CALCONST

Set new calibration constants, used to restore blown away constants

Channel, Calibration Gain1, Calibration Offset1, Calibration Gain2, Calibration Offset2,

Inflection Point

1,1,0,1,0, 0x2AAA

(0x8000000 for LTC ADC)

CALCONST?

Dump raw Calibration constants

Channel (1-2)

 

CALDATA?

Returns raw A/D counts for temperature and pressure along with uncalibrated voltage

Channel (1-2)

 

CALDATA1?

Same as above accept returns uncompensated pressure (psi) and temperate (°C) instead of voltage

Channel (1-2)

 

CALDATE

Override automatically generated calibration date

Automatically set when Cal command is issued.  Date is in the format MM/DD/YY, and allowable year values range from to 00-99.  Viewed on the display, the year will show up as four digits with leading ‘20’ added to the two digit year that was set by the CALDATE command. Optional 2nd parameter used as a flag to show on display or menus (0=don’t show, <>0 show).  If date is set to the default, it will not be displayed on power up or menu.

8/8/15,0

CALDATE?

Returns the Date of the last Calibration

 

 

CALNDUE

Override default calibration Next Due Date

Default is 1yr from last calibration.  Date is in the format MM/DD/YY, and allowable year values range from to 00-99.  Viewed on the display, the year will show up as four digits with leading ‘20’ added to the two digit year that was set by the CALNDUE command. Optional 2nd parameter used as a flag to show on display or menus (0=don’t show, <>0 show).  If date is set to the default, it will not be displayed on power up or menu

8/8/16,0

CALNDUE?

Returns the Date of the next calibration to be done

 

 

CHANNEL

Switch display to specified channel

1-4 (max is 1 for LC10)

3 = ch2 – ch1

4 = ch1 – ch2

3 and 4 only work if both channels 1 and 2 are pressure sensors

1

CHANNEL?

Get selected display channel

 

 

CUNIT  

Set custom unit parameters

If name is blank, custom units will be disabled in favorites.  Otherwise, it will be enabled.

Names longer than 8 characters will generate a “Too Large” error.

<name>,<offset>,<gain> 

Name = “CUSTOM “

Offset = 0.0

Gain = 1.0

CUNIT? 

Return custom unit’s parameters

 

 

CUNIT2  

Set second custom unit parameters.  If name is blank, second custom unit will be disabled in favorites.  Otherwise, it will be enabled.

Names longer than 8 characters will generate a “Too Large” error.

<name>,<offset>,<gain> 

Name = “CUSTOM2“

Offset = 0.0

Gain = 1.0

CUNIT2? 

Return second custom unit’s  parameters

 

 

DATA?

Return data buffer

 

 

DATE

Set the date

mm/dd/yy format 

11/11/15

DATE?

Get the current date

None

11/11/15

DISPLAY

Display Auto Power Down

0 (Never) to 255 minutes

NEVER

DISPLAY?

Query Display Auto Power Down setting

 

 

FAVORITES

Set Favorite Units

Bitmap summation of all units available.  Not all units are available for all gauge ranges (see Table 4).  Must have at least one valid unit set.

 

Custom units are not added to FAVORITES until a valid CUNIT, CUNIT2  command is received.

 

The FAVORITES setting only affects which units are included when using the front panel UNITS key to cycle through the display units. It does not restrict which units can be set with the UNITS command.

Value                       Bit  

    1 = atm                 0      

    2 = bar                 1

    4 = cmH2O@4°C            2

    8 = cmHg@0°C             3

   16 = ftH2O@39°F           4

   32 = inH2O@39°F           5

   64 = inHg@32°F            6

  128 = kgf/cm2                     7

  256 = kPa                 8

  512 = mbar                9

 1024 = mmHg@0°C            10

 2048 = MPa                 11

 4096 = oz/in2                       12

 8192 = psi                 13

16384 = Torr                14

32768 = Pa                  15

65536 = mmH2O@4°C            16

131072 = Custom1            17

262144 = Custom2            18

131071

FAVORITES?

Get Favorite Units

None

 

FETCH?

Display A/D Values

None

0.0

FETCH2?

Return current reading 1, max 1, min 1, reading 2, max 2, min 2, reading 3, max 3, min 3, reading 4, max 4, min 4

None

Notes: Readings 3 & 4 are only shown if channel 1 and 2 are both pressure sensors. Obviously, Readings 1 and 2 are only shown if the sensor is installed

 

FETCH3?

Returns readings on CH1-4 in psi or °C only

None

 

FILTER

Disables A/D reading filter or set the type of filter and how many readings to filter.

 

Sets Damping Filter window for fast changing signals

 

Sets Display Damping Filter

 

There are 4 types of Filters as follows:

1)  MOVING – The average of the last n readings. The oldest reading thrown out when next reading comes in.

2) REPEAT – the average of n new readings

3) MEDIAN – An odd number of new readings (n) are sorted and the middle ((n+1)/2) reading is the result. 

4) DAMPING – exponential filter based on the data acquisition rate and the time constant specified

 

Other Settings:

WINDOW – change in readings greater than this % of range reset filter.  Affects the DAMPING filter and the display damping filter.

OFF

 

 

 

WINDOW,0-100 (%) of range

 

 

DDAMP,(0-99.999)

 

 

 

MOVING, (2-11)

 

 

 

 

REPEAT, (2-11)

 

MEDIAN, (3, 5,7,9, or 11)

 

 

 

 

 

DAMPING, (0-999.999)

 

OFF

 

 

 

5%

 

 

0.25s

 

 

 

Moving = 10

 

 

 

 

Repeat = 10

 

Median = 5

 

 

 

 

 

Damping = 2.0

 

FILTER?

Returns the filter settings

None

-

FORMAT

Sets the Time and Date Formats.  Note that the date format that this command sets only applies to display.

12 or 24, 0-2

0 = YYYY/MM/DD

1 = MM/DD/YYYY

2 = DD/MM/YYYY

12, 0

FORMAT?

Returns the Time and Date Formats

None

 

*IDN?

Identify Unit

IEEE-488.2 compliant device discovery command

 

ILOOP

Set 4-20mA current loop channel

Channel (1-4)

1

ILOOP?

Return track channel

 

 

INTERVAL

Logging interval

1-65535s

1

INTERVAL?

Return logging interval

 

 

KEY

Simulate a keypress (useful for running test modes remotely)

L ((back)Light), H (Hi/Lo), P (Power), U (units), Z (Zero)

 

KEY?

Return last Key Pressed

 

 

LIGHT

Sets the LCD backlight level, and timeout  Does Low Cost gauge have an adjustable time-out?

0-100, 0 (never)  - 255 seconds

75, 60

LIGHT?

Query the LCD backlight level, and backlight timeout

 

 

LOG

Enable/Disable logging

START, STOP

STOP

LOG?

Return data logging state

 

IDLE

MINMAX

Reset Min/Max values

Channel (1-4)

 

MINMAX?

Returns Min/Max values

Channel (1-4)

 

NICKNAME

Sets Gauge nickname

1-24 printable ASCII characters

empty

NICKNAME?

Returns nickname

 

 

PCCON

Establish a Field Lab Session

START, STOP

inactive

PCCON?

Returns session status

 

 

PCKEY

Sets the Field Lab Session Key

10digit Hex Key

0000000000

PCKEY?

Returns the session key

None

0000000000

RANGE

Sets Lower and Upper range Values for bar graph and 4-20mA loop

Channel (1-4), LRV, URV

 

Default LRV & URV are the full range of the sensor in the current units

RANGE?

Queries LRV & URV for given channel

Channel (1-4) or MAX (optional)

MAX will return the full range of the sensor in the current pressure/temperature units.

 

RESET

Perform a system reset

None

-

RFAUTO

Set RF Auto Turn On

ON/OFF

OFF

RFAUTO?

Query RF Auto Turn On

 

 

RFCHAN

Set ZigBee RF Channel

Channels 11-26

26

RFCHAN?

Query ZigBee RF Channel

 

 

RTDCAL

Set RTD coefficients for use with external temp probe (TX/TY) on channel 2

RTD Temperature curve:

T(x) = a + b*x + c*x2 + d*x3, where

x = calibrated resistance measurement

-246.8037568 2.385004431

757.992612E-6

724.906794E-9

RTDCAL?

Returns RTD coefficients

None

-

RTDSN

Set RTD Serial Number

Up 15 character alpha-numeric

NONE

RTDSN?

Query RTD Serial Number

None

-

SAVE

Save the current system parameters as the defaults

None

-

SIZE?

Returns how many points are in the buffer

 

 

STATUS?

Returns unit status value from 0-255 (8-bit bitmap)

 

No parameters - bits mapped as follows:

•Bit 0 = Set if PCCON Start sent over USB. This would be cleared after PCCON STOP is sent over USB, USB is disconnected, or any reset occurs including power cycle.

•Bit 1 = Set if PCCON Start sent over RF. This would be cleared after PCCON STOP is sent over RF, RF is disconnected, or any reset occurs including power cycle.

•Bit 2 = Set if a Data Set has been Added (this happens on power up or after logging stops - which is how you actually have a named data set in the test mode display when logging is inactive) or deleted/aborted. This auto clears with STATUS?

•Bit 3 = Set if settings have changed from the menu. For example if somebody recalled a test mode in the middle of programming a test mode, the new test mode settings would be corrupted. This auto clears with STATUS?

•Bit 4 = Set if Units have changed. This auto clears with STATUS?

•Bit 5 = Set if the reading has updated. Useful when logging is active with an interval set. This auto clears with STATUS?

•Bit 6 = Set if Low Battery (0% remaining and not charging). Updated automatically.

•Bit 7 = Set if Min/Max? reset. This auto clears with STATUS?

188

SWITCH

Set Switch 1 and 2 state

Switch, Channel (1-4), Open Threshold, Close Threshold

If Close>Open Close on rising pressure, open on falling pressure/temp

If Open>Close Close on falling pressure, open on rising pressure/temp

Thresholds are in % of range (0-100)

1,1,48,52

2,1,52,48

SWITCH?

Query Switch state

 

 

TEMP

Set Temperature Units

C, F, K, or R

C

TEMP?

Read the internal temp sensor in degrees C

None

-

TIME

Set the time

hh:mm:ss format

12:00:00

TIME?

Get the current time

None

12:00:00

UNITS

Set the pressure units

 

01 = atm

02 = bar

03 = cmH2O@4°C

04 = cmHg@0C

05 = ftH2O@39°F

06 = inH2O@39°F

07 = inHg@32°F

08 = kgf/cm2

09 = kPa

10 = mbar

11 = mmHg@0°C

12 = MPa

13 = oz/in2

14 = psi

15 = Torr

16 = Pa

17 = mmH2O@4°C

18 = <custom unit #1>

19 = <custom unit #2>

14

UNITS?

Get the pressure units

None

14

VER

Displays the system version

None

-

ZERO

Zeroes out the displayed reading.  Warning message issued if attempting to zero when current pressure reading is 10% of full scale or more.

Channel (1-2), AUTO (or no parameter), OFF

OFF

ZERO?

Returns the Zero offset adjustment value

 

0.0

 

Serial Command Detailed Descriptions

 

AUTOPWR  - Set Auto Power Down Timeout (0-255min).  The gauge will physically power down after no commands or buttons are pushed for this timeout period.

AUTOPWR?  - Query Auto Power Down Timeout

> autopwr 0

 

> autopwr?

Timeout = Never

 

> autopwr 10

 

> autopwr?

Timeout = 10 minutes

 

BATT?  - Query Battery Info

> batt?

Voltage = 3.655 V

Counts = 0x27D

Capacity =  58%

 

CALCONST - Set calibration constants (Gain1, Offset1, Gain2, Offset2, Inflection Point as defined below).  Gains should be close to 1.0 and offsets should be close to 0.0.

CALCONST? - Get calibration constants.

Assume 100psi full scale pressure range:

Gain1 = (50.0-0.0) / (Uncalibrated Reading@50psi - Uncalibrated Reading@0psi)

Offset1= -Gain1 * Uncalibrated Reading@0psi

Gain2 = (100.0-50.0) / (Uncalibrated Reading@100psi - Uncalibrated Reading@50psi)

Offset2= 50.0 - Gain2 * Uncalibrated Reading@50psi

Inflection Point = Counts@50psi

> calconst? 1

9.931574e-01,-5.948951e-01,9.918741e-01,-5.295181e-01,0x03FADEA1

 

> calconst 1,3.2,23,43,2.3,0x45

 

> calconst? 1

3.200000e+00,2.300000e+01,4.300000e+01,2.300000e+00,0x00000045

 

> calconst 1,9.931574e-01,-5.948951e-01,9.918741e-01,-5.295181e-01,0x03FADEA1

 

CALDATA? - Returns uncalibrated pressure and temperature voltage readings along with raw counts.  Used in calibration and temperature compensation of the pressure and temp sensor. Counts are a signed 32-bit integer

CALDATA1? - Returns uncalibrated pressure (in psi) and temperature (in C) readings along with raw counts. 

> caldata? 1

0.464787,9440

> caldata1? 1

50.345,9440

  

CALDATE - Sets the date of calibration.

CALDATE? - Queries the date of the last calibration.

CALNDUE - Set the date of the next scheduled calibration.

CALNDUE? - Queries when the unit should be calibrated next.

NOTE – These dates are always MM/DD/YY and their output format is not affected by the FORMAT command.

> caldate?

Cal Date: 01/01/14

 

> caldate 5/7/14

 

> caldate?

Cal Date: 05/07/14

 

> calndue?

Next Cal Date: 01/01/15

 

> calndue 5/7/15

 

> calndue?

Next Cal Date: 05/07/15

 

> save

System settings saved in non-volatile memory.

 

DATE    - Set the date

DATE?  - Get the current date

NOTE – This date is always MM/DD/YY and their output format is not affected by the FORMAT command.

> date 13/13/13

Invalid Date!

 

> date 12/13/11

 

> date?

Date: 12/13/11

 

DISPLAY - Set Display Power Down Timeout (0-255min)

DISPLAY?  - Query Display Power Down Timeout

> display 0

 

> display?

Timeout = Never

 

> display 2

 

> display?

Timeout = 2 minutes

 

FAVORITES - Set Favorite units

FAVORITES? - Get Favorite units

> FAVORITES?

131071 (ALL)

 

> FAVORITES 8193

 

> FAVORITES?

8193 (ATM, PSI)

 

Table 2: Units Bit Map

Bit#

Units

Dec

Hex

18

Custom2

262144

40000

17

Custom

131072

20000

16

mmH2O@4°C

65536

10000

15

Pa

32788

8000

14

Torr

16384

4000

13

psi

8192

2000

12

oz/in2

4096

1000

11

Mpa

2048

800

10

mmHg@0°C

1024

400

9

mbar

512

200

8

kPa

256

100

7

kgf/cm2

128

80

6

inHg @32°F

64

40

5

inH2O@39°F

32

20

4

ftH2O@39°F

16

10

3

cmHg@0°C

8

8

2

cmH2O@4°C

4

4

1

bar

2

2

0

atm

1

1

 

FETCH? - Display A/D Value

> fetch?

CH0 Reading = 0.04 psi

CH1 Reading = 19.1 C

 

 

FETCH2? - Display A/D Value

> fetch2?

0.031psi,0.031,0.031,19.2C,20.01,18.2

 

  

FETCH3? - Display A/D Values in psi and °C only regardless of units setting

> fetch3?

0.031psi,19.2C

 

 

FILTER Set pressure reading filters

FILTER? – Query filter settings

> filter?

FILTER TYPE = REPEAT, 10 rdgs,

 

> filter MOVING, 8

 

> filter?

FILTER TYPE = MOVING, 8 rdgs,

 

> filter off

 

> filter?

FILTER TYPE = OFF

 

FORMAT  Set Time and Date formats

FORMAT? – Query Time and Date formats

> FORMAT?

12H, 0 (YYYY/MM/DD)

 

> FORMAT 24

 

> FORMAT?

24H, 0 (YYYY/MM/DD)

 

> FORMAT 12,1

 

> FORMAT?

12H, 1 (MM/DD/YYYY)

 

> FORMAT 12,1

 

> FORMAT?

12H, 0 (YYYY/MM/DD)

 

*IDN? – Display Identity

> *idn?

RALSTON INSTRUMENTS, MODEL LC20-GR-00-W1, LC-000029, v1.007.001 Jun 21 2019 12:01:42

 

KEY - Set a key press command

KEY?

> key h

 

>key z

 

>key l

 

>key u

 

>key p

 

 

LIGHT  Set the backlight level (0-100%) and timeout (0-255sec)

LIGHT? – Query the backlight level and timeout

> light 0,0

 

> light?

Level = 000%

Timeout = Never

 

> light 50,120

 

> light?

Level = 050%

Timeout = 120 seconds

 

MINMAX  Reset Min/Max data

MINMAX? – Query Min/Max data

> minmax? 1

Max Reading =   0.616 psi; Min Reading =   0.493 psi

 

> fetch?

A/D Reading =   0.588 psi

 

> minmax 1

 

> minmax? 1

Max Reading =   0.593 psi; Min Reading =   0.587 psi

 

NICKNAME  Set device nickname for FieldLab PC application to easily identify specific gauges.

NICKNAME? – Query nickname

> nickname Keith’s 100psi Gauge

 

> nickname?

Nickname = Keith’s 100psi Gauge

  

PCCON  Start/stop Field Lab PC application session

PCCON? – Query session info

> pccon?

PC connection is active.

Session timer = 763:39:09

 

> pccon stop

Session Ended

 

> pccon?

PC connection is inactive.

Session timer = 763:39:39

 

> pccon?

PC connection is inactive.

Session timer = 763:39:39

 

> pccon start

Session Established.

 

> pccon?

PC connection is active.

Session timer = 00:00:10

 

PCKEY  Set Field Lab application key.  Used to lock Field Lab sync data to a specific PC.

PCKEY? – Query Field Lab application key.

> PCKEY 1234567890

 

> pckey?

PC Key = 1234567890

 

RESET - Perform a system reset.  On USB, it is highly recommended to close the COM port immediately after sending this command and re-open it again once USB enumeration has finished.  Otherwise, windows may hold the com port open and not release it.

> reset

System Startup...

 

Ralston Digital Gauge

Version 0.001 - Built Dec 13 2011 14:33:41

  

SAVE - Save system parameters

> save

Settings saved.

 

STATUS? - Queries device status

> status?

Status = 0xBD

 

> status?

Status = 0x21

 

Table 3: Status Bits

Status Bit

Name

Decription

0

USBCON

Set if PCCON Start sent over USB. This would be cleared after PCCON STOP is sent over USB, USB is disconnected, or any reset occurs including power cycle.

1

RFCON

Set if PCCON Start sent over RF. This would be cleared after PCCON STOP is sent over RF, RF is disconnected, or any reset occurs including power cycle.

2

DATA

Set if a Data Set has been Added (this happens on power up or after logging stops - which is how you actually have a named data set in the test mode display when logging is inactive) or deleted/aborted. This auto clears with STATUS?

3

CFG

Set if settings have changed from the menu. For example if somebody recalled a test mode in the middle of programming a test mode, the new test mode settings would be corrupted. This auto clears with STATUS?

4

UNIT

Set if Units have changed. This auto clears with STATUS?

5

RDG

Set if the reading has updated. Useful when logging is active with an interval set. This auto clears with STATUS?

6

LOBAT

Set if Low Battery (0% remaining and not charging). Updated automatically.

7

MINMAX

Set if Min/Max? reset. This auto clears with STATUS?

 

TEMP - Change Units to C, F, K, or R

TEMP? – Query Temperature settings

> temp C

> temp?

INT Temperature = 25.1 C

  

TIME - Set the current time

TIME? - Get the current time

> time

ERROR: Invalid Time!

 

> time 17:56:30

 

> time?

Time: 17:56:33

  

UNITS - Set the pressure units

UNITS? - Get the pressure units

> units?

Units = (14) psi

> units 10

New Units = mbar

> units?

Units = (10) mbar


List of units

01 = atm

02 = bar

03 = cmH2O@4C

04 = cmHg@0C

05 = ftH2O@39F

06 = inH2O@39F

07 = inHg@32F

08 = kgf/cm2

09 = kPa

10 = mbar

11 = mmHg@0C

12 = Mpa

13 = oz/sqin

14 = psi

15 = Torr

16 = Pa

17 = mmH2O@4C

18 = < Custom >

19 = < Custom2 >


Table 4: Valid Units

Units

Sensor

Full scale(psi)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

GA

-15

X

X

X

X

X

X

X

X

X

X

X

 

X

X

X

 

 

X

X

GB

5

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

GC

-15 to 15

X

X

X

X

X

X

X

X

X

X

X

X

X

X

 

 

X

X

GD

15

X

X

X

X

X

X

X

X

X

X

X

X

X

X

 

X

X

X

GF

30

X

X

X

X

X

X

X

X

X

X

X

X

X

X

 

X

X

X

GH

50

X

X

X

X

X

X

X

X

X

X

X

X

X

X

 

X

X

X

GJ

100

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

 

X

X

X

GL

300

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

 

 

X

X

GN

500

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

 

 

X

X

GP

1000

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

 

 

X

X

GR

3000

X

X

 

X

X

X

X

X

X

X

X

X

 

 

 

X

X

GT

5000

X

X

 

X

X

 

X

X

X

X

X

X

 

 

 

X

X

GV

10000

X

X

 

X

X

 

X

X

X

X

 

X

 

 

 

X

X

GX

15000

X

X

 

X

X

 

X

X

X

 

X

 

 

 

X

X

GY

20000

X

X

 

 

X

 

X

X

X

 

X

 

 

 

X

X

GZ

30000

X

X

 

 

X

 

X

X

X

 

X

 

 

 

X

X

VER - Displays the system version

VER? - Displays the system version

> ver

 

Ralston LC Gauge

Version 0.001 - Built Dec 13 2011 14:33:41

 

ZERO- Enable/Disable zero

ZERO? - Get the zeroing settings

> zero? 1

Zero Value =   0.000 psi

 

> fetch?

CH1 Reading =   0.591 psi

 

> zero 1,0

 

> fetch?

A/D Reading =   0.000 psi

 

> zero? 1

Zero Value =   0.591 psi

 

Note that zeroing only applies to pressure sensors.  If a temperature sensor (e.g. RTD) is plugged into a channel and an attempt is made to set a zero value for that channel, the unit returns “Error: Invalid Configuration!”.  Attempting to zero a non-existent channel will return “Error: Invalid Channel!”

 

Example: With temperature sensor on channel 1.  Send

“zero 1,0.125”

Unit returns : “ERROR: Invalid Configuration!”.



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