SMAR HI302, User Manual

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Operation
5 . 4
HIRT block Operation
Once the configuration is stored in the HI302, the user should write TRUE in the
COMM_ENABLE parameter in order to operate it. When the communication is enabled,
the HI302 performs the following operations:
1. BLK_EXEC_STATE = IDENTIFICATION . HART device identification configured on each
HIRT block. It is done by using the command configured in the ID_CMD parameter, which
is located in the HIRT BLOCK. If after some RETRIES, the device does not respond, the
BLK_EXEC_STATE parameter of the corresponding HIRT block goes to
DEVICE NOT
FOUND . Check the block configuration, the device channel, polling address, the TAG, the
device, etc. If the ID_ METHOD parameter is in Automatic, a new identification attempt is
performed after 1 minute.
2. DEVICE_IDENTIFIED = TRUE e BLK_EXEC_STATE = UPDATING. After the initial
identification, the basic data are read and all corresponding parameters are filled. Such
data reading is based on the HCD block configuration selected in the HCD_SEL [1]
parameter. The identification and the reading process last approximately 10 seconds per
channel. Remember that, the 8 channels work normally in parallel, therefore, these initial
processes last approximately 40 seconds for the 32 devices (4 devices per channel). See
in the Appendix B, a list of all of the commands sent in this stage. During the UPDATING
process, only the reading commands are sent.
3. BLK_EXEC_STATE = UPDATED . Once the data have been identified and updated
successfully, the BLK_EXEC_STATE parameter goes to UPDATED, allowing access to
the HIRT parameters. Thus, all devices are polled, the dynamic variable values and the
device status are updated, if the HIRT.POLL_CTRL parameter is
Enabled . The update
frequency depends on the amount of HART device in the channel. The transaction for
each device takes approximately 1 second. For a 4-devices channel, the transaction may
take approximately 4 seconds. There are several parameters in the HCFG block that
check the HART communication according to the number of errors. Thus, they are useful
to solve configuration or installation problems.
IMPORTANT
The POLL_CTRL parameter should be set on Enabled to allow for the HI302 to poll the
device. In addition to updating the dynamic variables, the polling also updates the
parameters that depend on the RESPONSE_CODE parameter, for example, DS-65 and
DEVICE_STATUS. The polling is very important to detect device configuration changes,
so, the HI302 automatically updates the data.
4. IF any error occurs during the updating process, the block should go to PARTIALLY
UPDATED. See some reasons below:
•
The HART device does not support one of the sent commands. Check the
commands using the device documentation (see the Appendixes). Since
“Common Practice” commands are used, the user should filter them by using the
COMMON_CMD_CTRL parameter.
•
There was an error during the communication. Check the HCFG diagnostic
parameter to help you to solve the communication problem.
•
Set the block on OS and then, change it to AUTO for identification.
5. If the block is set on UPDATED , the user can associate the HIRT block with HVT block to
read any device variable.