User's Manual

Table Of Contents

Performing Advanced Functions

same value (or the number of requested values to zero). Then the RTU will

reply with only those flags set, which it can honor.

<Tlast> <last channel>: — Timestamp in UTC of the last received data and

last channel we received data for.

<max values>: — The maximum number of values requested.

<nr of channels>: — The number of channel number given in the following

field(s), 0 to return all available channels.

<channels ...>: — The number (i.e., identifier) of the logical channels we want

to retrieve data from.

<max packet size>: — Optional, 255 when omitted.

<Tto>: — Optional. The timestamp up to (and including) which data is requested.

If omitted, assume latest possible timestamp.

Data will be retrieved until one of the following limits is reached, be it availability of

data values, the maximal number of values requested, or the maximum radio

packet size which is reached.

REMARKS: This is a data retrieval command, local as well as remote.

RETURNS: The requested data if available is returned in the following format:

<rfin>: The RF value as the frame was received by the first receiving device. It is

an integer value in the range of 0 to 255.

<rfout>: The RF value as the request frame was received by the replying RTU.

<flags>: The capabilities and status of the RTU (see parameters).

The next set of fields is only available if there is any data received at all:

<last-saved-time_t>: The save timestamp of the first data value(s).

<number of values>: The actual number of values returned for this save-

timestamp of the reply.

<measured-values>+: At least one data record saved at the given <last-

saved-time_t>, which is comprised of:

<channel-no>: Number of logical channel this data belongs to.

<status>: Status and type of data:

• DATA_NOT_VALID 0x0fU

• DATA_NOT_AVAILABLE 0x07U

• DATA_VALID_BIT_0 0x00U

• DATA_VALID_BIT_1 0x01U

• DATA_VALID_BYTE 0x02U

• DATA_VALID_WORD16 0x03U

• DATA_VALID_WORD32 0x04U

• DATA_VALID_FLOAT 0x05U

• /* DATA_VALID_BYTEFIELD 0x06U */

• DATA_PARTIAL_BIT_0 0x08U