3.3.2 Functionality
Digital inputs
16 (24 V DC)
LED displays
for signal status, module errors, channel errors and supply voltage
Internal power supply
through the expansion bus interface (I/O-Bus)
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 con-
trol, cross-talk and stuck-at-1 tests, etc. are implemented in DI581-S according to IEC 61508 ed. 2 SIL 3
requirements.
DI581-S contains 16 safety digital input channels with the following features:
n
Phase-shifted (unique) test pulses T0 … T7 can be used for connection of mechanical sensors. Test
pulse outputs T0 … T7 provide 24 V signal with a short phase-shifted unique pulses (0 V) of 1 ms. Since
the test pulses on each of the test pulse output channels are unique (due to the phase shift), they can be
used to monitor the cross-talk between the given input channel with connected test pulse output and
another wire, e.g, with 24 V DC, another test pulse output, etc. Test pulse outputs are dedicated ones:
–
T0 can be used only with input channels I0 and I1
–
T1 can be used only with input channels I2 and I3
–
T2 can be used only with input channels I4 and I5
–
T3 can be used only with input channels I6 and I7
–
T4 can be used only with input channels I8 and I9
–
T5 can be used only with input channels I10 and I11
–
T6 can be used only with input channels I12 and I13
–
T7 can be used only with input channels I14 and I15
n
Input delay with the following values: 1 ms, 2 ms, 5 ms, 10 ms, 15 ms, 30 ms, 50 ms, 100 ms, 200 ms,
500 ms. Input delay value of 1 ms is the minimum one.
NOTICE!
The allowed signal frequency on safety digital inputs is dependent on the input delay value for the
given channel:
–
For channel input delay values of 1 … 10 ms, the pulse length of input signal shall be
³
15 ms
(~ 65 Hz) to avoid occasional input channel passivation.
–
For channel input delay of 15 ms, the pulse length of input signal shall be
³
20 ms (~ 50 Hz) to
avoid occasional input channel passivation.
–
For channel input delay of 30 ms, the pulse length of input signal shall be
³
40 ms (~ 25 Hz) to
avoid occasional input channel passivation.
–
For channel input delay of 50 ms, the pulse length of input signal shall be
³
60 ms (~ 15 Hz) to
avoid occasional input channel passivation.
–
For channel input delay of 100 ms, the pulse length of input signal shall be
³
120 ms (~ 8 Hz) to
avoid occasional input channel passivation.
–
For channel input delay of 200 ms, the pulse length of input signal shall be
³
250 ms (~ 4 Hz) to
avoid occasional input channel passivation.
–
For channel input delay of 500 ms, the pulse length of input signal shall be
³
600 ms (~ 1.5 Hz) to
avoid occasional input channel passivation.
AC500-S Safety Modules
DI581-S digital safety input module > Functionality
30.03.2017
AC500-S
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