Siemens SITRANS F M TRANSMAG 2, Руководство по эксплуатации, Страница: 46 / 114

Functions
7.4 Function Group Measuring Functions
SITRANS F M TRANSMAG 2
44
Operating Instructions, 11/2009, A5E00102775-07
● Limits, menu item 3.1.3, consisting of:
– Low Alarm Limit, menu item 3.1.3.1 and
– High Alarm Limit, menu item 3.1.3.2
The input is made in absolute values within the sensor limits (depending on the nominal
width, corresponding to -13 m/s to +13 m/s). Alarm limits of min. 10% and max. 90% of
the URV are set at the factory.
Exceeding or dropping below these limit values are signaled at digital output 1 or 2 if the
function of these outputs is configured appropriately (menu items 4.2.1 and 4.3.1). In
PROFIBUS communication, these events are reported by the limit bits in the measured
value status.
Note
Devices with PROFIBUS PA
The profile parameters for the "Low Warning Limit" and "High Warning Limit", can be set
independently of the alarm limits by acyclic PROFIBUS communication. They do not
appear in the local operating unit. Exceeding of the warning limits is only signaled by
PROFIBUS communication.
● Hysteresis, menu item 3.1.3.3
The limit values (menu items 3.1.3.1 and 3.1.3.2) can have a hysteresis added to prevent
"fluttering" of the switching output.
① Measured variable
② Limit alarm
③ Time
④ Hysteresis - limit max.
⑤ Hysteresis - limit min.
Figure 7-1 Limit value message and hysteresis