Analog modules
6.10 Analog input module SM 331; AI 8 x TC; (6ES7331-7PF11-0AB0)
S7-300 Module data
410 Manual, 06/2017, A5E00105505-AJ
Cycle time extension due to wire-break monitoring
The wire-break monitoring software function of the module is available in all operating
modes.
The 8-channel mode (hardware or software filter modes) extends module cycle times by
4 ms, irrespective of the number of channels at which wire-break monitoring is enabled.
In 4-channel mode (hardware filter), the module interrupts processing of input data for the
duration of 170 ms and performs a line continuity check. That is, each line continuity check
extends the module cycle time by 93 ms.
Unused channels
Set the "disabled" value at the "measurement type" parameter for unused channels. This
setting reduces module cycle times.
You must short-circuit all unused channels of an active group, that is, you short-circuit the
positive and negative inputs of these channels.
Effect of this measure:
● Measurement errors at the channels used of a group are avoided
● Diagnostic messages from the unused channel in a group are suppressed
Short-circuit to M or L
The module does not suffer any damage if you short-circuit an input channel to M or L.. The
channel continues to output valid data and does not report a diagnostics event.
Special features of channel groups with respect to hardware interrupts upon limit violation
You can set the high and low limits triggering hardware interrupts separately for each
channel in
STEP 7
.
End of cycle interrupt
You can synchronize a process with the conversion cycle of the module by enabling the end
of cycle interrupt. The interrupt is set when all active channels have been converted.
Table 6- 31 The table below shows the contents of the 4 bytes of additional OB40 information during process or end of
cycle interrupts.
Content of the 4 bytes with additional information
2 bits per channel to identify the range
High limit exceeded at channel
7 6 5 4 3 2 1 0 0
Low limit exceeded at channel
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