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1.1.3.
Properties of HART-capable devices
These are programmed into the unit during manufacturing, some can be configured using a HART MASTER, others cannot (they can be reconfigured only by the
manufacturer)
Short TAG
8 character device ID. Can be reconfigured.
Short address
Used to differentiate the 0…15 devices. There cannot be 2 identical „short addresses” in one system. Can be reconfigured
Message
A max 32-character arbitrary comment that can be assigned to the device and is generally operation-related.
Can be reconfigured
Descriptor
A max 16-character arbitrary comment that can be assigned to the device and is generally material-related.
Can be reconfigured
Date
Date. Can be assigned to the device. Can be reconfigured
Factory ID
Factory ID. For NIVELCO devices: 151, cannot be reconfigured
Device type ID
Device type ID, cannot be reconfigured
Device ID
The manufacturer’s electronic production number, cannot be reconfigured
The Factory ID, the Device Type ID and the Device ID together form the “Long Address”.
SW version
( Software version ):
Software version of the device (see device manual)
HW version
( Hardware version ):
Hardware version of the device (see device manual)
Apart from this, they provide the specification of the HART version according to which the device’s commands work
1.1.4.
HART Command set
We have seen how to build up a HART system. Using the HART commands, we can decide what the devices should do. Naturally, an ultrasonic transmitter needs
commands different from those of a temperature transmitter or maybe a valve, so quite a large number of commands would be needed. Every command has a one-
byte identifier. The 31
st
command enables expansion, and in this case the next 2 bytes form the code of a command (0…65535). HART commands can be divided in
to 3 classes:
universal commands 0..30
general commands 32..121
device-specific commands 128..253
In all cases, the commands contain an address (this can be short, long address, TAG), which determines the corresponding device.
Two devices with the same address cannot be connected together!!
Summary of Contents for MultiCONT
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