3 hart pass-through messaging – Spectrum Controls 1734sc-IE2CH User Manual
Page 49
Chapter 4: IExCH and HART
4-9
User’s Manual Pub. 0300257-01 Rev. A
HART Get Device Information - Reply packet structure
Offset
Field
Value
Definition
102-103
Expanded Device Type Code
(2 bytes)
CMD#0, Byte 2 if HART Rev < 7
CMD#0, Bytes 1-2 if HART Rev
>= 7
104-107
HART PV Lower Range
(4 bytes – Floating Point Value)
CMD#15, Bytes 3-6
108-111
HART PV Upper Range
(4 bytes – Floating Point Value)
CMD#15, Bytes 7-10
112-115
Damping Value
(4 bytes – Floating Point Value)
CMD#15, Bytes 11-14
116
Write Protect Code
(1 byte)
CMD#15, Byte 15
117
Pad_2 for alignment
(1 byte)
118 - 119
Private Label Mfg 16Bit
(2 bytes)
CMD#0, Byte 1 if HART Rev < 7
CMD#0, Bytes 19-20 if HART
Rev >=7
Sending the Get HART Device Information Message
The following rung will send an unconnected message to read the HART device
Information.
This is the message configuration dialog box
4.3.3
HART Pass-through Messaging
The HART Pass-Through Command can be used to send any HART command including
universal, common practice or device specific, directly to a field device via ladder.
All HART pass-through commands require a series of messages to be exchanged. First, a
pass-through init must be sent to the HART module to initiate the pass-through
command. The HART module will respond to the request with a request reply that
includes a handle that can be used to obtain the pass-through message response. Once the
handle is received, the user may issue a pass-through query to obtain the status of the
Get HART Device
Info Service Code
HART Instance 1
for Channel 0
HART Object Class