FunctionalityPermalink

This is the web edition of the original ‎⮫ AC500-S safety user manual, version 1.3.2. This web edition is provided for quick reference only. The original safety user manual must be used to meet functional safety application requirements.

Analog inputs

4 (0 ... 20 mA or 4 ... 20 mA)

LED displays

for signal status, module errors, channel errors and supply voltage

Internal power supply

through the I/O bus interface

External power supply

via the terminals ZP and UP (process voltage 24 V DC)

Self-tests and diagnostic functions (both start-up and runtime), like CPU and RAM tests, program flow control and cross-talk tests, etc. are implemented in AI581-S according to IEC 61508 SIL 3 requirements.

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Only F_Dest_Add is used for PROFIsafe F-Device identification in AI581-S.

AI581-S contains 4 safety analog input channels with the following features:

  • 14 bit resolution.

  • Checking of process power supply (diagnostic message is sent from the safety I/O module to the CPU informing about the lack of process power supply for the given safety I/O module). This function is a non-safety one and is not related to the internal safety-relevant over- and undervoltage detection.

  • Noise rejection 50 Hz or 60 Hz.

  • 1 channel (0 ... 20 mA), 1 channel (4 ... 20 mA) or 2 channel (4 ... 20 mA) modes (minimum or maximum value can be selected for transfer to safety CPU in 2 channel (4 ... 20 mA) mode; tolerance range 4 ... 12 % can be set for 2 channel mode).

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In a 2 channel mode, the lower channel (channels 0/2 ➔ Channel 0, channels 1/3 ➔ Channel 1, etc.) transports the aggregated process value, PROFIsafe diagnostic bit, acknowledgment request and acknowledge reintegration information. The higher channel always provides the passivated value "0".

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The maximal internal discrepancy time between two internal channel values (1 channel or 2 channel modes) in AI581-S module is 67.5 ms, which is also an internal worst-case input delay value.

The discrepancy time between two channel values (2 channel mode) with the selected supervised tolerance range (4 ... 12 %) is also 67.5 ms.

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The analog input channels have built-in hardware low-pass filter of 100 Hz.

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In case of the overcurrent/undercurrent detected at the safety analog input channel, the channel passivation takes place latest after 200 ms. The channel remains passivated for 30 s and then the check is performed if the overcurrent/undercurrent still present or not. If the overcurrent/undercurrent has gone, then reintegration request signal for the given channel is set to TRUE to allow channel reintegration.

The following table shows the mapping of safety CPU process values to the values in mA from AI581-S module. Two modes are defined for an analog input 0 ... 20 mA and 4 ... 20 mA.

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Both overflow and overrange represent an overcurrent. Both underflow and underrange represent an undercurrent.

Only in case of overflow and underflow, the analog channels are passivated and "0" process values are delivered to the safety CPU.

Range

0 ... 20 mA

4 ... 20 mA

Digital value (dec)

Digital value (hex)

 

Overflow*

 

:

> 23.519

 

:

> 22.81

32767*

:

32512*

7FFF*

:

7F00*

 

Overrange

23.519

:

20.000723

22.81

:

20.000578

32511

:

27649

7EFF

:

6C01

 

Nominal

range

20

 

:

 

0

20

:

16

:

4

27648

:

20736

:

0

6C00

:

5100

:

0000

 

Underrange

 

-0.000723

:

-1.481

 

3.999421

:

1.185

0 ... 20 mA

4 ... 20 mA

0 ... 20 mA

4 ... 20 mA

-1

:

-2048

-1

:

-4864

FFFF

:

F800

FFFF

:

ED00

 

Underflow*

 

< -1.481

 

 

 

 

< 1.185

 

 

 

0 ... 20 mA

4 ... 20 mA

0 ... 20 mA

4 ... 20 mA

-2049*

:

-32768*

-4865*

:

-32678*

F7FF*

:

8000*

ECFF*

:

8000*

* In these cases, the analog channels are passivated and "0" process values are delivered to the safety CPU.