
178 Siemens Simatic S7 Driver Online Help
See Also
Specifying Signal Conditioning in Database Manager
4BCD Signal Conditioning
Signal conditioning defines how the process database scales incoming data.
Parameters for 4BCD Signal Conditioning
Description 4-digit Binary Coded Decimal
(BCD) value.
Input Range 0 – 9999.
Scaling Scales 4-digit Binary Coded Decimal
values to the database block’s EGU
range.
Read
Algorithm
Reads from a 4-digit BCD register.
The Raw_value is then separated
into four nibbles (4 bits) prior to
scaling the value. Each nibble is
examined for a value greater than 9
(A-F hex). If a hexadecimal value
between A and F is found, a range
alarm is generated, indicating the
value is not within BCD range. Each
hexadecimal nibble between 0 and 9
is converted to a decimal value and
the resulting BCD value is scaled
with the following algorithm:
Result = ((BCD_value/9999) *
Span_egu) + Lo_egu.
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