Siemens SITRANS F M TRANSMAG 2, Руководство по эксплуатации, Страница: 52 / 114

Functions
7.5 Function Group Device Outputs
SITRANS F M TRANSMAG 2
50
Operating Instructions, 11/2009, A5E00102775-07
7.5 Function Group Device Outputs
Analog out (Menu item 4.1)
This menu only appears in devices with a 20 mA output (7ME5034-0xxxx and -2xxxx).
The following settings are possible:
● Current limiting, menu item 4.1.1
The upper current limit for the output signal is determined in this menu item.
22.5 mA
20.0 mA
0
① Current
② Parameter range
③ Measured value
Figure 7-4 Current limiting
● Failure signal, menu item 4.1.2
In the event of a fault, e.g. a device error or measuring error due to entrapment of air, the
analog output shows a predefined current.
The following settings are possible:
– 3.6 mA
– 22 mA
– 24 mA
– Hold for a defined time (5...240 seconds), then 3.6 mA
– Hold permanently
With the "Hold 5 s" setting you can bypass temporary faults (e.g. air entrapment in the
medium) for up to about 5 s without the analog signal outputting an error message.
The same applies accordingly for "Hold 20 s", "Hold 40 s" etc. The last valid measured
value is output during the fault. If the fault lasts less than 5 s the current measured
value is output at the end of the fault. If the fault persists, the output signal is set to 3.6
mA.
In the "Hold permanently" setting the last valid value is output until the fault is
eliminated.
In the current range between 0 and 20 mA, the 3.6 mA failure signal or "Stop" is not
recommended; in this case, the setting ’22 mA’ or ’24 mA’ must be selected.