Spectrum Controls 1734sc-IE2CH - Manual (Page 41)

User’s Manual Pub. 0300257-01 Rev. A
Chapter 4
IExCH and HART
This chapter describes how to read and write HART data using the IExCH module. This
chapter includes the following sections:
•
HART features
•
Detecting HART devices
•
Auto scanning of HART dynamic variables
•
Supported HART CIP messages
Section 4.1
HART Features
The IExCH module will function as a HART master and will communicate with HART
devices running HART revision 5 or greater. Ther IExCH module includes one HART
modem per channel to provide maximum acquisition speed and flexibility. The block
diagram in section 1.6.2 describes the internal architecture of the module including the
placement of the HART modems. The module performs the following HART operations:
•
Automatically reads the four dynamic HART variables PV,SV,TV, and FV
•
Automatically retrieves and stores HART device information including,
manufacturer’s ID, device tag name, HART revision level, etc., and makes the
information available via a CIP unconnected message
•
The module automatically retrieves and stores extended device status, using
HART command 48. The extended status can be retrieved using an
unconnected CIP message.
•
A HART pass-through interface using CIP unconnected messaging provides the
ability for the user, or remote client, to send a HART command to a HART
enabled device.
Section 4.2
Detecting HART
Devices
HART communication can be enabled independently on each channel. For more
information on configuring HART on a specific channel, refer to Chapter 3. When a
channel is enabled for HART, the IExCH module will act as a primary HART master and
the HART enabled field device will act as a HART slave. Any given channel may have a
master (i.e. the IExCH), a secondary master (hand held configuration tool), and a slave
device connected simultaneously. Please see figure below.