TLP — Target-Link-Protocol — Standard Protocol

In case there is no library available yet for your control system, you can emulate the protocol between control system and Connector by referring to the following documentation. Please contact us first in this case, as we are continuously developing libraries for additional control systems.

Standard Protocol

With each SQL request to the database, the Connector is provided with information prior to execution.

Request to the Connector

Attribute	Data Type	Description	Default
MRP	Nullterminierter String	Max Return Parameter
<MRP Value>	Nullterminierter String	Minimum 1	Nicht optional
MR	Null-terminated String	Max Rows
<MR Value>	Null-terminated String	Minimum 1	Not optional
MC	Null-terminated String	Max Columns
<MC Value>	Null-terminated String	Minimum 1	Not optional
MS	Null-terminated String	Max String
<MS Value>	Null-terminated String	Minimum 1	Not optional
MB	Null-terminated String	Max Buffer
<MB Value>	Null-terminated String	Maximum amount of data in bytes which the control system can read	Not active
CT	Null-terminated String	Connector Timeout
<CT Value>	Null-terminated String	0 = no Timeout, Connection remains open, >0 = Timeout in seconds	Not active
CN	Null-terminated String	Column Names
<CN Value>	Null-terminated String	0 = no Column names, 1 = Column names (default 1)	1
CS	Null-terminated String	Cut String
<CS Value>	Null-terminated String	String of each value is shortened to length CS	Not active
S	Null-terminated String	String (SQL Request)
<S Value>	Null-terminated String	Minimum 1 character	Not optional
T	Null-terminated String	Transmit Request

<MRP><NUL><MRP Value><NUL>	Maximum number of return parameters which can be stored in the control system
<MR><NUL><MR Value><NUL>	Maximum number of datasets which can be stored in the control system
<MC><NUL><MC Value><NUL>	Maximum number of columns which can be stored in the control system
<MS><NUL><MS Value><NUL>	Length of the string variable in the control system
<MB><NUL><MB Value><NUL>	Maximum amount of data in bytes which the control system can read (optional)
<CT><NUL><CT Value><NUL>	Timeout Connector (optional)
<CN><NUL><CN Value><NUL>	A database request also returns the column names in addition to the data, or not. (optional)
<CS><NUL><CS Value><NUL>	A database request also returns data if the size of the database value exceeds the defined maximum string length (MS). The value will be cut off after the CS value, and the error is ignored. (optional)
<S><NUL><S Value><NUL>	SQL request string
<S><NUL><S Value><NUL>	If the SQL request string is too large for the control system, it can be sent to the connector in a dissected form. (optional)
<T><NUL>	Start command to send the SQL request string to the database

Examples:

MRP_NUL15_NULMR_NUL80_NULMC_NUL40_NULMS_NUL255_NULS_NULSELECT id, iParam1, fParam2, sText1 FROM tTable1_NULT_NUL

MRP_NUL15_NULMR_NUL80_NULMC_NUL40_NULMS_NUL255_NULCS _NUL80_NULCN_NUL0_NUL
S_NULSELECT id, iParam1, fParam2, sText1 FROM tTable1_NUL
S_NULWHERE id < 4_NUL
T_NUL

Response from the Connector

Attribute	Data Type	Description
RS	Null-terminated String	Return State
<RS Value>	Null-terminated String
RP	Nullterminierter String	Return Parameter
<RP Value>	Nullterminierter String
RR	Null-terminated String	Result Rows
< RR Value>	Null-terminated String
RC	Null-terminated String	Result Columns
< RC Value>	Null-terminated String
RN	Null-terminated String	Result Column names
< RN Values>	Null-terminated String
RD	Null-terminated String	Result Data
< RD Values>	Null-terminated String

<RS><NUL><RS Value><NUL>

RS Value = 0: Okay, data will follow. RS Value > 0: Error code, no data will follow.

If RS Value = 0:

<RP><NUL><RP Value><NUL>	RP Value = Number of return parameters
<RR><NUL><RR Value><NUL>	RR Value = Number of datasets
<RC><NUL><RC Value><NUL>	RC Value = Number of columns

Only if RP Value > 0 return parameter will follow (RPD)

RPD_NUL
123_NUL321_NULabc_NUL

If RC Value > 0 data will follow, else RR Value contains the number of the processed datasets (Update, Delete…)

<RN><NUL>	Followed by all column names
<RD><NUL>	Followed by all data

Column names (RN) are enumerated as:

For iC = 1 to RC
    <RN Value[iC]><NUL>
Next iC

Data values (RD) are enumerated as:

For iR = 1 to RR
    For iC = 1 to RC
        <RD Value[iR, iC]><NUL>
    Next iC
Next iR

Example:

RS_NUL0_NULRP_NUL3_NULRR_NUL3_NULRC_NUL4_NUL
RPD_NUL
123_NUL321_NULabc_NUL
RN_NUL
id_NULiParam1_NULfParam2_NULsText1_NUL
RD_NUL
1_NUL501_NUL10.1_NULText Example 1_NUL
2_NUL502_NUL10.2_NULText Example 2_NUL
3_NUL503_NUL10.3_NULText Example 3_NUL

Error Codes Return-Value

Error Number	Error Description
0	No error, request data to follow
1	Unknown SQL Command
2	Request returns more datasets than defined by MaxRows, modify request or increase MaxRows
3	Request returns more columns than defined by MaxColumns, modify request or increase MaxColumns
4	Request returns more data than defined by buffer size (only with target type Siemens) Modify request or increase Buf. Size in the Connector and in the application.
5	Request returns minimal one value that is bigger than defined by MaxStringLength, modify request or increase MaxStringLength
10	Internal Connector error
11	Internal Connector error, cannot open database
23	Request string is empty
24	Number MaxRows not defined
25	Number MaxColumns not defined
29	Size MaxStringLength not defined
>100	Error numbers of the ODBC database connection (some known error numbers are attached)
40002	General error during SQL request, request string is invalid

Handshake

Error-free Request

Abortion during Request

Error during Request