Siemens SIMATIC S5-90U System Manual page 488

Function Modules
Function
The counter module can be used as an up-counter or as an up/down counter for a position decoder.
The counting pulses are supplied by a sensor that you can connect to the 15-pin subminiature D
female connector of the module. You can choose from two types of sensors that fulfill the following
requirements.
• 5-V error voltages according to RS 422 (up to 500 kHz)
• 24-V signals (up to 25 kHz)
As additional inputs, the module has an enable input and a reference input connected to terminals
on the 10-terminal strip that is on the bottom of the bus unit.
By using the STEP 5 program, you can assign two setpoints via the I/O bus. These setpoints are
output to channels 0 and 1 in the I/O slot for the module. Once the counter status reaches one of
these values, the respective output completes the circuit at terminal block (Q0 or Q1). The status of
the outputs is displayed in the diagnostic byte in status bits S1 and S2.
You can also read the following values by using the STEP 5 program.
• The updated count (load IW channel 1 and 2)
• The diagnostic byte (load IW channel 0 high byte)
You can preselect the following items on the operating mode switch.
• Function mode (counter/position decoder)
• Position resolution (X1, X2, or X4)
• Input voltage range of the sensor (5 V DC or 24 V DC)
PD
SV
Figure 16-8. Switch Positions on the Operating Mode Switch
16-20
2×
4×
24 V
S5-90U/S5-95U
Position decoding (PD)
Counter (C)
Pos. resolution single
Pos. resolution double
Pos. resolution quadruple
not allowed
Sensor connection 5 V
Sensor connection 24 V
EWA 4NEB 812 6115-02b