Siemens FST020, Function Manual, Page: 65 / 194

Setup
3.4 Inputs and outputs
FST020 Function manual
Function Manual, 09/2017, A5E42949526-AA
63
● Medium temperature
● Kinematic viscosity
All process values are available for analog output channel 2 and frequency output channel 4.
The accuracy specified for the analog output signal applies only within the range 4 to 20 mA.
Lower limit (4 mA) and upper limit (20 mA) can be assigned to any specific flow values.
①
Linear control range
②
Lower saturation limit
③
Upper saturation limit
④
Lower fault current value
⑤
Recommended setting range for lower fault current
⑥
Recommended setting range for upper fault current
⑦
Measuring range
Figure 3-1 Current limits for NAMUR configuration
The fail safe current output signal can be selected to:
● Lower fault current (defined in the Loop current scale selection)
● Upper fault current (defined in the Loop current scale selection)
● Last valid value (the last process value before the failure occurred)
● Current value (actual measured value)
● Fail-safe value (within the range of 0 mA to 25 mA
1)
)
1)
For channel 1 the range is 3.5 mA to 25 mA
Output scaling configuration
Below are four examples describing configuration possibilities for a current output.