Heartbeat - Honeywell Vertex M Technical Handbook

Vertex M 24-Point Continuous Monitor
TM
If the concentration is non-zero and a fault exists, the
concentration value will take priority and be reported. It
is not possible to detect the existence of maintenance
faults from the concentration outputs.
Unlike previous Honeywell Analytics products, the full-
scale value of the concentration output is not equal to
the full scale value of the gas table by default. Instead
the full scale (31206 count) level defaults to twice the
threshold limit value (TLV). Therefore an output of
12482 counts corresponds to a gas concentration of
0.5 TLV and 18723 counts corresponds to 1.0 TLV by
default. This can be altered by editing the configuration
profile as shown in Figure
Figure A-2. Configuration Profile
For more information on the configuration profile see
Section 3.6.4 Configure
If the concentration data is to be used only for
visualization and datalogging, it may be more
convenient to capture this information through OPC.
See Section A.2 OLE for Process Control (OPC)
Interface. This avoids the requirement of scaling the
value to get actual concentration. The concentration is
available through the highly-reliable fieldbus for those
customers who wish to make shutdown decisions
based on concentrations instead of alarm levels.
Appendix A - Network Interface and Options
A-2.
Point.
A.3.3 Heartbeat
A heartbeat counter is provided with some of the
fieldbusses in word 40. This increments every second
to confirm that the internal PLC is running and that
communications is working. External equipment
communicating with the Vertex M via Ethernet/CIP,
LonWorks or Profibus must verify that this value is
changing to be certain that the PLC is operating.
Each optional fieldbus interface is implemented using
commercial communications modules connected to
the internal PLC. In the Vertex M the modules function
as slaves only, although the hardware may be capable
of acting as scanners or masters when installed
elsewhere.
F-10