Siemens LR 460 Analog Input Function Blocks 1, Electronics temperature, How the AIFBs work

J; Profi;e structure PA

Electronics temperature

The Level Transducer Block also monitors the internal temperature of the device electronics. If the temperature exceeds permitted limits, it does not change the sensor value, but it does change the status.The permitted limits correspond to those of the permitted ambient temperature.

If a temperature limit is exceeded, the status changes. Peak indicators1 allow you to check the maximum and minimum temperatures that have occurred.

Analog Input Function Blocks 1 and 2

There are two identical Analog Input Function Blocks which operate independently. The figure below shows how measured values are processed within the Analog Input Function Block (AIFB1 or AIFB2) to produce the device output, which is communicated via cyclic transfer to PROFIBUS PA, and displayed on the LCD.

Analog Input Function Block function groups (simulation, mode and status)

Operator						Operator
		Simulate
		Parameter
		enable				OUT	MAN
		simulate					Out of
						no	Service	Alarm
		value and							OUT
						output		Limit
Process Variable	2	status	on		FB
				Value			AUTO	Check	Value Status
						Fail-safe
from TB					algorithm
(Function Block
input)						MODE and
					Status
Value Status			off			STATUS
						handling

How the AIFBs work

The Analog Input Function Blocks allow you to control modifications to the output value (PROFIBUS cyclic data).

1.Open View menu, scroll down to Peak Values, and click on Temperature tab in the Peak Values window.

2.The output from the Level Transducer Block can be called the Primary Value (or Secondary Value). When it becomes the input to the AIFB, it is called the Process Variable.

Page J-102 SITRANS LR 460 (PROFIBUS PA) – INSTRUCTION MANUAL 7ML19985JM01