MESIT Devices communication protocol
Description
Communication line configuration
Communication station configuration
I/O tag configuration
Literature
Changes and modifications
Revisions of document
Description
MESIT Devices protocol is a binary protocol intended for communication with capacitive level sensor produced by MESIT. The current implementation supports reading its data space.
Communication line configuration
Communication line category: Serial, SerialOverUDP Device Redundant
Parameters of the asynchronous line according to design and type of connection of device:
- standard settings from the manufacturer: 38400 Baud, 8 data bits, no parity, 1 stop bit
Communication station configuration
Communication protocol: MESIT Devices
The station address is a decimal number that is intended for addressing a device on a data bus with more SLAVE devices.
Station protocol parameters
Parameters may be entered in the dialog window of station configuration - Parameters tab. These parameters may be defined:
Table 1
Full name | Description | Unit | Default value |
---|---|---|---|
Full Debug | Received and sent data are recorded in the communication log. | - | YES |
Master Address | A decimal number that identifies a sender (D2000 KOM). | - | 1 |
Wait First Timeout | First waiting for a response after sending a request. | Ms | 100 |
Wait Timeout | Waiting between individual readings of the response. | Ms | 100 |
Retry Timeout | Waiting before repeating a request. | Ms | 100 |
Max. Wait Retry | Maximum retries of reading response. | - | 6 |
Retry Count | Maximum retries of sending a request. | - | 2 |
I/O tag configuration
Allowed types of I/O tags: Ai, Ci, Di, TxtI, TxtO
I/O tag address consists of four parameters separated by a full stop. The format is: "M.R.O.L", where:
- M - defines a number of the message (0-255)
- R - defines the type of request (0-65535)
- O - offset - a byte number (1, 2, etc.) in a received response where the first (lowest) byte is located
- L - length of a request (in bytes) count that must be read from the received response. For numerical types of I/O tags, the values of parameter "L" can be only 1, 2, and 4. For text types of I/O tags, this parameter is limited by the maximum length of the data block of response.
All these parameters are entered as decimal numbers.
As an example, we may mention the reading of fuel temperature. It is read with the help of message number 0x0C and request type 0x50. In the response, this information is in two bytes that start with offset 0x09. It means, the address of I/O tag is "12.80.9.2".
Output I/O tag addressing
In addition to reading data, the protocol supports also the writing of values into device memory. It is performed with the help of text output I/O tags. The format of I/O tag address is M[.R][#Vh[.Vd]]
- M - message number (0-255)
- R - optional application type (0-65535)
- Vh - optional message number of the reply to the sent message header (0-255). If a message with a message number other than Vh arrives in response, the writing will be considered unsuccessful. If Vh is not specified, each response is considered a positive confirmation.
- Vd - optional message number of the reply to the sent message data (0-255). If a message with a message number other than Vd arrives in response, the writing will be considered unsuccessful. If Vd is not specified, each response is considered a positive acknowledgment.
Addresses of I/O tags for Capacitive level meter type LM1.2134:
Table 2
Address | I/O tag type | Description |
---|---|---|
3.79.1.1 | Ci | Basic data - level meter status. The documentation states the following possible values:
|
3.79.2.4 | Ai | Basic data - the volume of fuel in the tank. Linear conversion required A = 0.001, B = 0, the result is volume in liters. |
3.79.6.4 | Ai | Basic data - relative permittivity. Linear conversion required A = 0.001, B = 0, the result is relative permittivity. |
3.79.10.4 | Ai | Basic data - fuel temperature in °C. |
3.105.1.2 | TxtI | Identification - text part of the serial number (two characters). |
3.105.3.2 | Ci | Identification - numeric part of the serial number (2-byte value 0-65535). |
3.105.5.9 | TxtI | Identification - 9-character product number (tested sample had "LM1.21345"). |
3.105.14.8 | TxtI | Identification - 8-character firmware version (tested sample had "LM1-2.50"). |
4.68 4.68#228 | TxtO | Calibration - clear the current calibration curve by entering an empty value "". |
4.83 4.83#235.233 | TxtO | Calibration - write a new calibration curve. In the value of the I/O tag it is necessary to enter individual bytes in decimal form, which are separated by a "#" character. |
6 6#220 | TxtO | Setting the time filter parameters. In the value of the I/O tag it is necessary to enter 2 bytes in decimal form, which are separated by a "#" character, in the form "Time#Type", e.g. "10#0", where:
|
7 7#231 | TxtO | Setting theft conditions. In the value of the I/O tag it is necessary to enter 6 bytes in decimal form, which are separated by the character "#", in the form "PeriodL#PeriodH#LossL#LossH#TimeL# TimeH", e.g. "60 # 0 # 1 # 0 # 10 # 0", where:
|
9.70.1.1 | Ci | Time filter - time filter period (in seconds). The setting is possible within setting the time filter parameters. |
9.70.2.1 | Di | Time filter - hardening of the time filter. A value of TRUE means that it is a working machine and that filter hardening is switched on. The setting is possible within setting the time filter parameters. |
9.75.1.2 | Ci | Theft condition - fuel loss measurement period (in seconds). The setting is possible within the setting of theft conditions. |
9.75.3.2 | Ci | Theft condition - the maximum allowable loss of fuel (in liters) for the period during which it is not yet theft. The setting is possible within the setting of theft conditions. |
9.75.5.2 | Ci | Theft condition - the time of the length of switching on the status output when theft is detected (in seconds). The setting is possible within the setting of theft conditions. |
12.78.1.2 | Ai | Accelerometer - the tilt of the X-axis. Linear conversion A=0.006, B=-180 is required, the result is an angle from the interval <-90°… 90°>. |
12.78.3.2 | Ai | Accelerometer - the tilt of the Y-axis. Linear conversion A=0.006, B=-180 is required, the result is an angle from the interval <-90°… 90°>. |
12.78.5.2 | Ai | Accelerometer - the tilt of the Z-axis. Linear conversion A=0.006, B=-180 is required, the result is an angle from the interval <-90°… 90°>. |
12.78.7.2 | Ai | Accelerometer - acceleration of the X-axis. Linear conversion A=0.002, B=-8 is required, the result is acceleration in g from the interval <-8 … 8>. |
12.78.9.2 | Ai | Accelerometer - acceleration of the Y-axis. Linear conversion A=0.002, B=-8 is required, the result is acceleration in g from the interval <-8 … 8>. |
12.78.11.2 | Ai | Accelerometer - acceleration of the Z-axis. Linear conversion A=0.002, B=-8 is required, the result is acceleration in g from the interval <-8 … 8>. |
12.78.13.2 | Ai | Accelerometer - X-axis calibration offset (deviation from the horizontal plane at the time of calibration). Linear conversion A=0.006, B=-180 is required, the result is an angle from the interval <-90°… 90°>. |
12.78.15.2 | Ai | Accelerometer - Y-axis calibration offset (deviation from the horizontal plane at the time of calibration). Linear conversion A=0.006, B=-180 is required, the result is an angle from the interval <-90°… 90°>. |
12.78.17.2 | Ai | Accelerometer - Z-axis calibration offset (deviation from the horizontal plane at the time of calibration). Linear conversion A=0.006, B=-180 is required, the result is an angle from the interval <-90°… 90°>. |
12.80.1.2 | Ai | Fuel quality - bioindex. Linear conversion A=0.03125, B=0 is required, the result is a bioindex in % of the interval <0 … 100>. |
12.80.3.2 | Ai | Fuel quality - viscosity. Linear conversion A=0.0003052, B=0 is required, the result is viscosity in mm2/s from the interval <0 … 20.00>. |
12.80.5.2 | Ai | Fuel quality - density. Linear conversion A=0.0003052, B=0 is required, the result is density in kg/dm3 from the interval <0 … 20.00>. |
12.80.7.2 | Ai | Fuel quality - relative permittivity. Linear conversion A=0.00012207031, B=0 is required, the result is relative permittivity from the interval <0 … 5.000>. |
12.80.9.2 | Ai | Fuel quality - temperature. Linear conversion A=0.0003052, B=0 is required, the result is a temperature in °C from the interval <-55.0 … +125.0>. |
12.80.11.4 | Ai | Fuel quality - volume at 15 ° C. Linear conversion A=0.001, B=0 is required, the result is the volume in liters adjusted to a temperature of 15 °C from the interval <0 … 10000.0>. |
Literature
Changes and modifications
- May 2015: completion of I/O tag configuration
Revision of document
- Ver. 1.0 – December 3, 2014: implementation of a protocol
- Ver. 1.1 - May 26, 2015: completion of I/O tag configuration
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