Rockwell Automation 1770-HT8 SMART TRANSMITTER - Manual (Page 75)

Communicating with the Smart
Transmitter Interface
Chapter 4
Communicating with the Smart Transmitter
Interface
4-10
HART Address
When field devices respond to HART polls they send packets with the
same short or long frame address format used in the poll. The field device
sets or clears the master address bit depending on which master the
response is for. If the device is also bursting data, it sets the burst mode
address bit; otherwise it clears this bit. You must program the host
processor to verify that the address field in a HART Response packet is
correct before it processes the remaining data in the packet.
Figure 4.6
HART Response or Burst Data Packets Ć HART Field Device to Smart Transmitter
Interface (Short Frame Format)
90071
HART Command
Short Frame HART Address
HART Delimiter
Byte Count
Response Code
Data
Check Byte
Slave Adddress Bits
Logical Address Bits
Device Burst Mode Bit
0 Disabled
1 Enabled
Master Address Bit
0 Secondary
Master
1 Primary Master
Frame Type
001 Burst Frame
110 ACK Frame
Reserved
Long/Short Frame Bit
0 Short
1 Long
0 0 0 0 0
Preamble
When the host processor requests data from the Burst Data table, the
packet that is received contains either a short frame or long frame address,
depending on the field device which sent that data to the Smart Transmitter
Interface. The master address bit may also be in either state, as field
devices alternate this bit between primary and secondary master when
bursting data.