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ELGAS-2 (CP II) communication protocol

Supported device types and versions 
Communication line configuration
Communication station configuration
I/O tag configuration
Changes and modifications
Document revisions

Supported device types and versions

The protocol supports the communication with ELCOR-2 and microELCOR-2 devices (made by the ELGAS company ) that recalculate a gas quantity.

Communication line configuration

The asynchronous transmission parameters are set according to the setting of a specific device.

Communication station configuration

  • Communication protocol: Elcor ELGAS-2 (CP II).
  • Station address:
    • Node address: value in the range of 0 to 65535.
    • Address: meter address, a value in the range of 0 to 255.
    • If both addresses are 0, the device must answer obligatorily.

Password for reading: maximum of 6 characters is allowed if the password is set in the device (ELCOR-2 only).

Station protocol parameters

Configuration dialog box  - tab „Parameters".
They influence some optional parameters of the protocol. Following station protocol parameters can be set:

Table 1

Full nameMeaningUnitDefault value
Device Type
Selection of device type.ELCOR-2 or microELCOR-2ELCOR-2
Retry Count
The delay between request retries in case of a communication failure.
Wait First Timeout
Delay after sending the request before reading the response.ms100 ms
Wait Timeout
Delay between response readings until it is completed.ms100 ms
Max. Wait Retry
Retry count of response reading until it is completed.
Static Data Read Period
Static - configuration data read period (microELCOR-2 only).min60 min
Hourly Archive Periodic Reading
A period for the reading of hourly archives (0-60 min). Value 0 disables the reading.min0 min
Wake Up Sequence Length
Length of 'wake-up' data sequence, which is sent before the request after a longer communication pause.0 .. 50 bytes25 bytes
Wake Up Each Query
Insert 'wake-up' data sequence before each request.YES/NONO
Wake Up Character
Form 'wake-up' data sequence from the specified characters.0 .. 255255
Group Source Address
Group source address (address of the D2000 KOM process).0 .. 655350
Source Address
Source address (address of the D2000 KOM process).0 .. 2550
Full DebugA high level of communication tracking, the received values of I/O tags and other debug information is shown.YES/NONO

I/O tag configuration

Possible value types of I/O tags: Di, Ai, Ci, TxtI, TiA.

The ELCOR-2 device

Table 2 contains the list of main parameters of the device.
Tables 3 to 8 contains the list of variable configuration and informative data according to the parameter type. DESC(ind) parameter represents the common data of all parameters. It describes the quantity. The current value of quantity can be acquired by the configuration of the I/O tag with numerical address - index ind (number from 1 and higher). To find out the technical units - configure text of I/O tag with address UNIT(ind).

Table 2 - Device parameters - Main device parameters

Object descriptionValue typeAddressUnits
The serial number of the deviceCi, TxtISN
Referential temperatureAiTB°C
Referential pressureAiPBkPa
Firmware versionTxtIFW
Station nameTxtIDESC
CO2 concentrationAiTAB(0)%
N2 concentrationAiTAB(1)%
Heat of combustionAiTAB(2)MJ/m3
Relative densityAiTAB(3)
H2 concentrationAiTAB(4)%
H2S concentrationAiTAB(5)%
He concentrationAiTAB(6)%
H2O concentrationAiTAB(7)%
O2 concentrationAiTAB(8)%
Ar concentrationAiTAB(9)%
CO concentrationAiTAB(10)%
C1H4 concentrationAiTAB(11)%
C2H6 concentrationAiTAB(12)%
C3H8 concentrationAiTAB(13)%
iC4H10 concentrationAiTAB(14)%
nC4H10 concentrationAiTAB(15)%
iC5H2 concentrationAiTAB(16)%
nC5H2 concentrationAiTAB(17)%
C6H14 concentrationAiTAB(18)%
C7H16 concentrationAiTAB(19)%
C8H18 concentrationAiTAB(20)%
C9H20 concentrationAiTAB(21)%
C10H22 concentrationAiTAB(22)%

Table 3 - Device parameters - Analog values

Object descriptionValue typeAddressUnits
Analog value - transducer serial No.TxtI, CiSN(ind)
Analog value  - the upper limit of measuring rangeAiHL(ind)
Analog value  - the lower limit of measuring rangeAiLL(ind)
Analog value - technical unitsTxtIUNIT(ind)
Analog value - nameTxtIDESC(ind)

Table 4 - Device parameters - Counter

Object descriptionValue typeAddressUnits
Counter - serial number of gas meterTxtI, CiSN(ind)
Counter - technical unitsTxtIUNIT(ind)
Counter - nameTxtIDESC(ind)

Table 5 - Device parameters - Error counter

Object descriptionValue typeAddressUnits
Error counter - primary counter numberTxtI, CiCNT(ind)
Error counter - technical unitsTxtIUNIT(ind)
Error counter - nameTxtIDESC(ind)

Table 6 - Device parameters - Standard counter

Object descriptionValue typeAddressUnits
Standard counter - primary counter numberTxtI, CiCNT(ind)
Standard counter - calculation numberTxtI, CiCLC(ind)
Standard counter - technical unitsTxtIUNIT(ind)
Standard counter - nameTxtIDESC(ind)

Table 7 - Device parameters - Conversion factor

Object descriptionValue typeAddressUnits
Conversion factor - analogue (pressure) numberCiCNTP(ind)
Conversion factor - analogue (temperature) numberCiCNTT(ind)
Conversion factor - pressure error volumeAiDEFVALP(ind)kPa
Conversion factor - temperature error volumeAiDEFVALT(ind)°C
Conversion factor - compressibility error volumeAiDEFVALK(ind)
Conversion factor - technical unitsTxtIUNIT(ind)
Conversion factor - nameTxtIDESC(ind)

Table 8 - Device parameters - Standard flow rate

Object descriptionValue typeAddressUnits
Standard flow rate - primary flow numberCiCNT(ind)
Standard flow rate - calculation numberCiCLC(ind)
Standard flow rate - technical unitsTxtIUNIT(ind)
Standard flow rate - nameTxtIDESC(ind)

The microELCOR-2 device

As an address of the I/O tag, also the data from "Address" or "Alternate address" columns can be used.

Table 9 - Actual values

Object descriptionValue typeAddressDefault addressUnits
Primary volumeAiOH.1Vm3
Standard volumeAiOH.2VNNm3
Error primary volumeAiOH.3VESTm3
Error standard volumeAiOH.4VNESTNm3
Primary flow rateAiOH.5Qm3/hour
Standard flow rateAiOH.6QNNm3/hour
Compressibility ratioAiOH.7K
Actual pressureAiOH.8PkPa
Actual temperatureAiOH.9TK
Calculation numberAiOH.10Z
Device temperatureAiOH.11TPR°C
Operating value - rest (only in VF input)AiOH.12VZB

Table 10 - Service data

Object descriptionValue typeAddressDefault addressUnits
Type + serial numberTxtISE.1VCE
The serial number of the temperature sensorTxtISE.2VCT
The serial number of the pressure transducerTxtISE.3VCP
Version SW+HWTxtISE.4VER
Customer numberTxtISE.5CZ
The serial number of the gas meterTxtISE.6PVC
Network addressTxtISE.7ADR
Constant of gas meterCiSE.8KP0=1, 1=0.1, 2=0.01, 6=100, 7=10
Measuring intervalCiSE.9IM
Interval of data sending through a serial lineCiSE.10IV
Start hour of the gas dayCiSE.11CD
Start of measurementTiASE.12DSM
Date and time of the deviceTiASE.13DAT
Battery capacityCiSE.14BAT%
Actual statusTxtISE.15OS
Configuration bytesTxtISE.16KB
The communication speed of a serial lineCiSE.17RK4=4800, 5=9600, 6=19200
CRC 51CiSE.18C1
CRC MSP 430CiSE.19C2
Battery voltageAiSE.23UPRHEXV
Display configurationCiSE.24KDIS
Bits of permission to write the itemsTxtISE.25W_RUN
Customer's regionTxtISE.26REGION
Saving interval in the hourly archiveCiSE.27IU
Quantity of diff. pulses between IMP and IMP1CiSE.28IMP1_PI0=off, 255=on permanently
Input pulse ratioCiSE.32I_V_DP
Bits of write permission in RUN by a userCiSE.33WU_RUN
Actual status 2CiSE.34OS2
The setting of pulse ratio of gas meter VF on m3CiSE.35KPVF

Table 11 - Parameters

Object descriptionValue typeAddressDefault addressUnits
Base pressureAiPA.1PNkPa
Base temperatureAiPA.2PT°C
Default pressureAiPA.3PESTkPa
Default temperatureAiPA.4TEST°C
Default compressibility levelAiPA.5SK
Min. pressure limitAiPA.6PMINkPa
Max. pressure limitAiPA.7PMAXkPa
Min. temperature limitAiPA.8TMIN°C
Max. temperature limitAiPA.9TMAX°C
Limit of max. flow rateAiPA.10QMAXm3/hour
Method of compressibility calculationCiPA.11MK
CO2 concentrationAiPA.12KCO2%
N2 concentrationAiPA.13KN2%
H2 concentrationAiPA.14KH2%
Relative densityAiPA.15KD%
Heat of combustionAiPA.16KHONkWh/m3

Table 12 - Minimums/maximums

Object descriptionValue typeAddressDefault addressTechnical units
Pressure under the limitAiMI.1PMMINkPa
Time of pressure under the limitTiAMI.2DPMMIN
Pressure above the limitAiMI.3PMMAXkPa
Time of pressure above the limitTiAMI.4DPMMAX
The temperature under the limitAiMI.5TMMIN°C
Time of temperature under the limitTiAMI.6DTMMIN
Temperature above the limitAiMI.7TMMAX°C
Time of temperature above the limitTiAMI.8DTMMAX
Flow rate above the limitAiMI.9QMMAXm3/hour
Time of flow rate above the limitTiAMI.10DQMMAX
Time of reset of minimums/maximumsTiAMI.11DNUL

Parameters and minimums/maximums are read in a period which is set by the Static Data Read Period protocol parameter.


  • Description of system μ-ELCOR and microELCOR-2 - operating schedule (Elgas 1. 6. 2006)
  • Reference books of producer ELGAS s.r.o.

Changes and modifications


Document revisions

  • Ver. 1.0 - April 22th, 2009 - the creation of the document.

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