CMD_USDT_SET_STMIN

Back to USDT Commands CMD_USDT_SET_STMIN_MULT

Command:             CMD_USDT_SET_STMIN_MU;T
Destination:         SD_USDT
Destination Channel: Vehicle Network Protocol Channel ID

Description

Clients use this command to set the STmin multiplication factor of the USDT server for a given client and channel number. STmin is the minimum amount of time allowed between consecutive messages sent to a device. It is present in the first flow control message from the device. The units of STmin are milliseconds. This command allows the units to be adjusted by a registered USDT client program.
By default, the STmin multiplication factor is set to 1.00. This results in the delay time between messages being equal to that specified in the first flow control message. This will result in the delay time being between 0 and 255 milliseconds in 1.0 millisecond steps. If the STmin multiplication factor is set to 0.5, the delay time between messages will be between 0 and 127.5 milliseconds in 0.5 millisecond steps. The STmin multiplication factor can be set to any value between 0.0 and 100.0. For values greater than 1.0, the delay time between messages will be greater than that specified by STmin.
The time delay between messages is provided by the Delay driver. In order to get the desired time delay between messages, the time resolution of the Delay driver may need adjusting. The default time resolution is 1.0 milliseconds. If the STmin multiplication factor is set to 0.5 and STmin from the flow control message is 1, the desired delay between messages is 0.5 milliseconds. With the default time resolution, two messages will be sent out back to back every millisecond. This may work for some devices. However, if the time resolution of the Delay driver is changed to 0.5 milliseconds, one message will be sent every half millisecond which may work with more devices.
Not all devices may accept messages sent faster than that specified by STmin in the first flow control message. Use this command with caution.

Command Data Format

STmin multiplication factor in floating point format

4 bytes

STmin Multiplication Factor
This is the STmin multiplication factor in floating point format. Its value should be between 0.0 and 100.0. The four bytes of the value must be in little endian order which is the default order for x86 computers.

Response Data Format
none

Response Return Codes

RESP_OK Execution of the command was successful.

RESP_INVAL_CHAN The specified channel is invalid.

RESP_MEM_ALLOC_ERR Could not allocate enough memory for data buffers.

RESP_UNSUPPORTED This command is not supported on the specified channel.

RESP_INVAL_LEN The number of bytes present for the IDs/Headers is incorrect according to the number of IDs/Headers in the third byte of data.

RESP_INVAL_PARAM The client is not registered with the USDT server.

RESP_UNREG The specified source channel is not registered with the server.

RESP_UNKNOWN_ERR An unknown error occurred.

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RESP_OK	Execution of the command was successful.
RESP_INVAL_CHAN	The specified channel is invalid.
RESP_MEM_ALLOC_ERR	Could not allocate enough memory for data buffers.
RESP_UNSUPPORTED	This command is not supported on the specified channel.
RESP_INVAL_LEN	The number of bytes present for the IDs/Headers is incorrect according to the number of IDs/Headers in the third byte of data.
RESP_INVAL_PARAM	The client is not registered with the USDT server.
RESP_UNREG	The specified source channel is not registered with the server.
RESP_UNKNOWN_ERR	An unknown error occurred.