Defining Channel Descriptions; Latching Feature - Emerson Rosemount 702 Reference Manual

Operation
5.2

Defining channel descriptions

The 702 provides four device variables:
•
•
•
•
•
•
5.3

Latching feature

The Rosemount 702 has a latching feature that, when enabled, allows detection of
momentary state changes to be held for a configurable latch period. The latching feature
can be configured to detect either high or low state changes. By default, the Plunger state
(channel 1) is enabled to latch high state changes for a period of one minute.
The following are some examples to demonstrate how the latching time works.
Note
Hold time is set to four seconds for illustration in the following examples.
Short events (less than latch hold time) of the measured value will be latched to the
reported value for the duration of latch hold time.
50
Plunger arrival state (channel 1) – By default when a plunger event is detected, this
value state will indicate "True" and will remain true for the duration of the
configured latching time. A reported value of "False" indicates that a plunger event
has not been detected. Other reported values can also be configured, refer to
AMS Wireless Bench Config.
Plunger arrival counts (channel 1) – Reports the number of plunger state transitions
that have occurred since the last reset.
Power savings state (channel 2) – By default power savings state is set to "False."
This indicates that power is being provided from the 702 to the plunger arrival
sensor. The setpoint for this variable can be set to "True" which would remove
power from the sensor if desired. WARNING - This is an advanced setting and not
recommended for most applications. When power is removed, plunger arrival states
WILL NOT be detected. If more information on this feature is desired contact your
local sales representative.
Power saving counts (channel 2) – Reports the number of times power savings state
has been enabled. (This would normally be reported at zero for most applications).
Electronics temperature – This indicates the internal operating temperature of the
device. For normal operation, this should be within the limits specified in
Section 9.3.3. The value can be configured to report either Celsius or Fahrenheit, see
AMS Wireless Bench Config.
Supply Voltage – This indicates the effective voltage delivered by the power module.
When the voltage falls below 6V, the power module should be replaced soon. When
the voltage falls below 5.2V the 702 will no longer provide plunger state
measurements and the power module must be replaced to restore proper
operation.
702 Wireless Discrete Transmitter