Spectrum Controls 1756sc-OF8H Series A - Manual (Page 85)

Chapter 7: HART Channel Configuration, Data, and Status 71
Figure 7.4 (Connected and Unconnected messaging)
Connected
Unconnected
• Analog data
• Module status
• HART Dynamic
Variables
• HART device codes
• Module Configuration
• Any CIP message
• HART Pass-Through
The module uses the two communication schemes to gather HART data.
Gathering HART data is accomplished using two processes auto
acquisition, and or using the module specific commands.
Auto Acquisition Auto Acquisition Auto Acquisition Auto Acquisition Auto Acquisition
When a channel is configured for HART, the module will automatically
search and establish a connection to any HART field device wired to the
channel. Once the module establishes a connection it will begin to acquire
HART data, including device specific codes (i.e. Manufacturer ID, serial
number, etc.), the four dynamic variables, extended device status, slot
variables (OF8H only), and any stored ASCII message descriptor that
may be present. The HART data retrieved automatically by the module is
then displayed in the input image and is accessible by ladder logic. The
HART data will update, on average, every 6.5 seconds if all eight channels
are enabled for HART. The module initiates the connection by sending a
string of HART commands to the field device. Please see figure below.