Endress+Hauser Levelflex M FMP 40 Operating Instructions Manual page 56

5 Operation
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56
5.5.8 Scaling of the output data
The on-site display and the digital output are working independently of each other.
On-site display
The on-site display always displayes the main value V0H0 directly from the Transducer
Block.
Digital output
For the digital output this value is rescaled in two steps:
PV_SCALE_MAX
from Transducer
V0H0
block
PV_SCALE_MIN
0
1. In a first step, the main value is mapped to the interval [0;1]. PV_SCALE_MIN and
PV_SCALE_MAX determine the limits of this mapping.
2. In a second step, the interval [0,1] is mapped to the interval [OUT_SCALE_MIN,
OUT_SCALE_MAX]. The value resulting from this mapping is transfered via V6H2 to
the PLC.
Note!
The scaling of the ouptut value is required by the Profibus profiles. It prevents uncont-
rolled jumps of the output value when one changes the unit of the measuring value in
the Transducer Block. If units are changed, PV_SCALE_MIN and PV_SCALE_MAX auto-
matically adapt themselves in such a way that the output value remains unchanged.
Only after confirming the change by the "Set unit to bus" (062) function,
OUT_SCALE_MIN is set equal to PV_SCALE_MIN and
OUT_SCALE_MAX equal to PV_SCALE_MAX.
Thereby the new unit also becomes effective at the output.
Caution!
If a linearisation has been carried out, it must be confirmed by the "Set unit to bus"
(062) function in order to become effective at the digital output.
Levelflex M FMP 40 with PROFIBUS-PA
1
0
1 AI_OUT
OUT_SCALE
(V6H2)
MIN
OUT_SCALE
MAX
PLC
Endress+Hauser