Pilz PSSu E S 2AI U - Manual (Page 19)

Function description
Operating Manual PSSu E S 2AI U(­T)
21405­EN­03 19
4.2.4 Limit values
The module has range monitoring and limit value monitoring on each channel:
} Range monitoring
} Upper limit value: 4095
D
– Lower limit value: ­4095
D
– The module compares the upper and lower limit value with the digital value after the
hardware calibration (values with 12 bits plus sign) and writes the result of the com­
parison as follows:
– System environment A:
– In the status byte (see "PSSu assignment in system environment A")
– System environment B:
– In the I/O data element "Overrange" or "Underrange" (see "PSSu assignment in
system environment B").
– The limit of the measuring range corresponds to 4095
D
.
} Limit value monitoring
} Limit value 1
– Limit value 2
– The module compares limit value 1 and limit value 2 with the digital value after scal­
ing (values with 15 bits plus sign) and writes the result of the comparison as follows:
– System environment A:
– In the status byte (see "PSSu assignment in system environment A")
– System environment B:
– In the I/O data element "LimitValue1" or "LimitValue2" (see "PSSu assignment in
system environment B").
– The limit of the measuring range corresponds to 32 767
D
with default scaling val­
ues.
You can change the default values in the system software.
The decimal value for the PSSuniversal Configurator (n) is calculated from the analogue
value at the input (U
Limit
) as follows:
n = 32 768 * U
Limit
/ 10 V
Example:
} Voltages at the input, which are to be monitored through the limit values:
– Limit value 1 is to be ­8 V.
– Limit value 2 is to be 5 V.
} Entry in the PSSuniversal Configurator:
– Limit value 1 corresponds to ­26 214
– Limit value 2 corresponds to 16 384