Siemens Sitrans LR250, Руководство по эксплуатации, Страница: 263 / 306

Appendix B: PROFIBUS PA profile structure
B.2 Block Model
SITRANS LR250 (PROFIBUS PA)
Operating Instructions, 08/2014, A5E32221386-AC
261
Electronics temperature
The Transducer Block monitors the internal temperature of the device electronics. A change in
temperature can provide advance warning of a possible device failure, and allow for preventive
maintenance.
If a temperature limit is exceeded, the output value is unchanged but the output status changes.
(The permitted limits correspond to those of the permitted ambient temperature.)
Peak indicators allow you to check the maximum and minimum temperatures that have
occurred. To see peak temperature values, Open the menu View – Device Diagnostics, select
Device Status, and click on the tab Device Status.
B.2.1.3 Analog Input Function Blocks 1 and 2
The input to the AIFB is a value with a status. See Transducer Block function groups (Page 258)
for a graphic representation.
Output conversion
The Analog Input Function Blocks can modify the output value.
Scaling
Output Scaling (2.6.6.) allows you to scale the output to any desired units.
Fail-safe
If the status of the input (TB output value or Simulation Value) is bad, the fault logic can output
either the last usable measured value, or a given substitute value. Set Fail-safe Mode (2.6.9.)
and, if desired, define a value in Value (2.6.9.2.).
Device/input simulation
You can define a simulated value to be input to the AIFB instead of the output value from the
Transducer Block. The simulated value allows the AIFB to be tested independently of the
characteristics of the environment.
Actual Mode: Device / Output Simulation
Actual Mode allows you to select one of three possible outputs.
Actual Mode
(2.6.2.)
Description Output value
AUTO automatic the automatically-recorded measured value
MAN manual a manually-set fixed simulation value
O/S function block disabled the preset safety value.