Siemens SIMATIC ET 200S Operating Instructions Manual page 146

1Count5V/500kHz
3.6 Count Modes
Switch at comparison values
The comparator switches the output when the following conditions are met:
• The two comparison values must be loaded using the load functions CMP_VAL1 and
• After the comparison values are loaded, the DO1 output must be enabled with
The following table shows you when the DO1 is switched on or off:
V2 < V1 (see Figure below)
V2 = V1
V2 > V1 (see Figure below)
The comparison result is indicated by the status bit STS_CMP1. You can only acknowledge
and thus reset this bit when the comparison condition is no longer fulfilled.
There is no hysteresis in the case of this output behavior.
It is not possible to control the DO1 output with the SET_DO1 control bit in the case of this
output behavior.
146
CMP_VAL2, and
CRTL_DO1.
DO1 is switched on when
V2 ≤ count ≤ V1
V2 = count = V1
V1 > count
or
count > V2
DO1 Is switched off when
V2 > count
or
count > V1
V2 ≠ count ≠ V1
V1 ≤ count ≤ V2
Technological Functions
Operating Instructions, 02/2007, A5E00124867-05