Analog Modules
4-96
Programmable Logic Controllers S7-300 Module Data
A5E00105505-03
Short circuit to M or L
If you short an input channel to M or L, the module does not suffer any damage.
The channel continues to issue valid data; neither is a diagnosis reported.
Overflow, underflow and hardware interrupt limits
The diagnosis operating limits for overflow and underflow for some of the
measuring ranges differ from those given in section 4.3.1 of the manual. In some
cases, numerical methods in the module software for evaluating the process
variables prevent values up to 32511 being signaled.
Hardware interrupt limits must not be set to values greater than the smallest
possible limit value of the overflow or underflow operating limits for the
end-of-scan-cycle interrupt in section 4.3.1.
End-of-scan-cycle interrupt
By enabling the end-of-scan-cycle interrupt, you can synchronize a process with
the conversion cycle of the module. The interrupt occurs when the conversion of all
the enabled channels is complete.
Table 4-58 Content of the 4 bytes with additional information from OB40 during a hardware
interrupt or an end-of-scan-cycle interrupt
Content of the 4 bytes with
additional information
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
Byte
Special
2 bits per channel to identify the range
analog
markers
Upper limit exceeded
in channel
7 6 5 4 3 2 1 0 0
Lower limit exceeded
in channel
7 6 5 4 3 2 1 0 1
End-of-scan-cycle
event
X
2
Unassigned bit 3