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10 

Control

Alicat ASCII Serial Communication

Alicat ASCII Serial Terminal is a pre-configured program for serial communications via the 

instrument’s 6-pin connector. Download Serial Terminal for free at 

alicat.com/drivers

.

Serial commands are not case-sensitive. In the descriptions below, however, the commands 

are shown in uppercase while command variables are shown in lowercase to help differentiate 

them.

All commands must be prefixed with the unit_id, the unique identifier for the instrument. 

Instruments will also accept commands beginning with *, which is used as a broadcast value. 

The unit_id must be the first character after a carriage return (

  ).

Unless otherwise noted, there must be a space between the command and any arguments. 
All commands must end with a carriage return (

  ), decimal value 13, hex value 0x0D). 

After a carriage return is received, the instrument does not start acting upon or responding 

to a command until the serial idle timeout is reached (the time needed to transmit 3.5 bytes).
All responses are a single line terminated with a carriage return. If a new command is started 

before the carriage return of the response of the previously issued command has been 

received, the behavior of the instrument is undefined.

Establishing Communication

Connect the instrument to a computer through a COM port or virtual COM port, noting the 

COM port number. Up to 26 instruments can be connected to a single COM port.
The following are the default connection settings:

•  Baud

: 38400 (se

page 17

)

•  Data bits

: 8 

•  Parity

: none 

•  Stop bits

: 1 

•  Unit ID

: A  (se

page 16

)

Data Frame Format

Data can be read from the instrument as the complete data frame, or you can choose specific 

data to report. The complete data frame is:

+24.57  +100.0 +0021513.0 +100.0 

+55.13 

N2 

[TOV][MOV][OVR][HLD][VTM]

unit _ id temp.  flow   total 

setpoint valve _ drive gas Error Conditions

where:

unit _ id

:  

The text ID of the instrument.

temperature

The current temperature of the instrument, in °C.

flow

The current flow reading of the instrument, in the configured units.

Total

The total volume (read from the totalizer)

setpoint

The current setpoint value, in the same units as flow.

valve _ drive

:   The valve drive will be reported in percent of full drive.

gas

:  

The currently selected gas.

If present, the following error condition abbreviations indicate:

TOV

 

Temperature overrange.

MOV

 

Mass flow overrange.

OVR

 

Totalizer overrange.

HLD

 

Valve hold is in use (see 

page 13

).

VTM

 

Valve thermal management is active (see note below).

Содержание ALICAT BC Series

Страница 1: ...OPERATING MANUAL FOR MASS FLOW INSTRUMENTS BASIS 2 METERS AND CONTROLLERS...

Страница 2: ...ibration BASIS 2 instruments are factory calibrated When operated per instructions regular maintenance is not required Periodic inspection and recalibration can ensure ongoing performance and accuracy...

Страница 3: ...g the use or operation of this instrument please contact us using the information on page 2 Alicat offers many combinations of instrument sizes accessories connections and configurations These custom...

Страница 4: ...nges 14 Taring the Instrument 14 Autotare 15 Active Gas 15 Totalizer Reset 15 Totalizer Batch 15 Totalizer Configuration 16 Full Scale Flow 16 Unit ID 16 Serial Number 16 Version Number 16 MODBUS Addr...

Страница 5: ...g Green Power is applied serial activity is occurring Fast Red Blink Mass overrange temperature overrange totalizer overrange etc Slow Red Blink Valve override in effect Mounting Mount the instrument...

Страница 6: ...first two threads entering the instrument This will minimize the possibility of tape entering the flow stream and clogging the flow path Face seal fittings can be installed without Teflon tape applie...

Страница 7: ...7 Getting Started Pin Function 1 Analog Setpoint Input 2 Analog Signal Output 3 Ground 4 Power In 12 24V 5 Serial RS 232 Rx or RS 485 B 6 Serial RS 232 Tx or RS 485 A...

Страница 8: ...g to increase response speed and stability for some applications Establishing Communication To connect your instrument to FlowVision 2 0 1 Download FlowVision 2 0 from alicat com flowvision and instal...

Страница 9: ...field to use a percentage instead of a unit of measure d Resume clears the direct drive and returns to closed loop control 2 The totalizer limit mode shown in Instrument Settings Totalizer is unique...

Страница 10: ...ponse of the previously issued command has been received the behavior of the instrument is undefined Establishing Communication Connect the instrument to a computer through a COM port or virtual COM p...

Страница 11: ...64 Current batch remaining 128 Instrument Status Add the table values to request multiple data which will be returned in the order they appear in this table The total value must be an integer from 1...

Страница 12: ...log input To read the current setpoint ramp rate unit_idSR To set a new setpoint ramp rate unit_idSR max_ramp_rate time_units max_ramp_rate is the new maximum setpoint ramp rate The value is a non neg...

Страница 13: ...from 0 65535 The larger the igain the more aggressively the controller will correct errors between the commanded setpoint and the measured process value Example aLCG 500 5000 sets pgain to 500 and ig...

Страница 14: ...will be unit _ id time avg _ temp avg _ flow where unit _ id The text ID of the instrument time The elapsed time that data has been acquired in milliseconds avg _ temp The average temperature during t...

Страница 15: ...Methane To read the active gas unit_idGS To set the active gas unit_idGS gas_number gas_number is an integer from the table above Example aGS 8 flow methane on instrument A When reading or setting th...

Страница 16: ...olume totalizer batch 2 Maximum temperature Example aFPF 2 returns the max temperature for Instrument A The data returned will be unit _ id value units where units is a text string indicating the unit...

Страница 17: ...described in this manual to Protocol 1 described in the BASIS 1 manual To read the current command protocol unit_idP To switch from Protocol 2 to 1 unit_idP 1 To switch from Protocol 1 to 2 unit_idP2...

Страница 18: ...t the response to function code 6 Write Single Register will echo the value provided by the master in the write and not the value of the register after the write For example if the setpoint register w...

Страница 19: ...register 524 To set the desired setpoint write the setpoint as a signed 2 byte integer to register 33524 The setpoint is equal to the value after formatting with the factory set number of decimal plac...

Страница 20: ...register 53 Batch Dispensing Batch dispensing controllers only flows a set volume of gas after which the valve closes and flow stops You can repeat batches To read the volume remaining for the curren...

Страница 21: ...the selected gas remains unchanged Added in V3 0 0 2101 R 1 If set there is a mass flow overrange MOV condition 2 If set there is a temperature overrange TOV condition 4 If set there is a totalizer o...

Страница 22: ...least significant register of the average flow of the last measurement address 4214 is read Added in V3 0 0 4201 R W The number of samples to take in a measurement an unsigned integer Each sample is...

Страница 23: ...e Valve drive value 100 Added in V3 0 0 4210 R The minimum flow measured in the previously completed measurement a signed 2 byte integer Flow is equal to the value after formatting with the factory se...

Страница 24: ...scale range of the flow an unsigned 4 byte integer in SCCM 39 W Write 0xAA55 43605 to tare instrument flow Note that performing a tare will interrupt any currently executing measurement 45 R W The MOD...

Страница 25: ...eger 0 3000 Reference temperature C value 100 Added in V2 4 0 53 W Write 0xAA55 43605 to reset the total volume to 0 Added in V2 5 5 54 R W The totalizer behavior when the total volume reaches the max...

Страница 26: ...available when the setpoint is being set via MODBUS communication and the Setpoint Source is set to unsaved digital see page 11 All other setpoint sources ASCII saved digital analog are not impacted b...

Страница 27: ...the current instrument total volume units indicated in register 49 and scale formatted with the factory set number of decimals Added in V3 0 0 524 525 R W The maximum setpoint ramp controllers only Th...

Страница 28: ...anage the setpoint using pin 1 analog in of the 6 pin connector The voltage current sent to the controller is proportional to the full range of the instrument The setpoint value should correspond line...

Страница 29: ...n tape As noted on page 6 never tape the first two threads entering the instrument to help avoid this issue Issue My flow readings are negative Action Negative flow readings under no flow conditions c...

Страница 30: ...has entered your instrument do not take apart the flow body to clean it as this will negate its NIST traceable calibration Please contact support for cleaning page 2 Recalibration BASIS 2 instruments...

Страница 31: ...ubic meter per hour Sm d Nm3 d Cubic meter per day SCIM Cubic inch per minute SCFM Cubic foot per minute SCFH Cubic foot per hour SCFD Cubic foot per day Temperature Units C Degrees Celsius Time Units...

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