Rosemount 702, Справочное руководство

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Reference Manual
00809-0200-4702, Rev BA
June 2010
5-7
Rosemount 702
Figure 5-9. Leak Sensor Not
Connected - AMS Device
Manager Overview screen
Table 5-1. Liquid Hydrocarbon
Detection Interface, for Modbus
mapping
Table 5-1 describes use of the 702 Discrete Transmitter for hydrocarbon detection in other
communications protocols such as Modbus or OPC. It is imperative that both PV and SV be
mapped to the host system so as to make a good interpretation of the condition and status of the
leak detector.
IMPORTANT NOTICE
It is imperative that both PV and SV be mapped to the host system so that the diagnostic
information on the sensor status is captured.
In addition, system considerations must be observed to ensure that the device is still connected
to the wireless network and reporting values. On an Emerson Smart Wireless Gateway, this can
be done by referring to the parameter: PV_HEALTHY. PV_HEALTHY has a “True” state when the
device is on the network and its updates are current, not late or stale, and the device is
functioning properly. A “False” state of PV_HEALTHY means that the device is either off of the
network, the data updates are not current, or that there is a malfunction of the device (such as an
electronics failure). In the case of a “False” state of PV_HEALTHY, it is recommended to assume
that the device is not connected to the network and to take appropriate action.
Below is a shot of the gateway screen where the PV, SV and PV_HEALTHY variables and
parameter can be mapped.
PV SV Description / Interpretation
1.0 1.0 Normal condition, no leak detected, sensor status good
0.0 1.0 or 0.0 Leak detected, sensor status good
1.0 0.0 Sensor Not Connected, Assume Leak, take appropriate action