Siemens SIMATIC S5-90U System Manual page 410

Module Spectrum
Start-Up of Module
Set the intended operating mode using the operating mode switch of analog input module 464-
8MA11. The switch is located on the right side at the top of the front panel of the module.
Power supply Set the switch to the available power supply frequency. This selects the inte-
frequency: gration time of the A/D converters for optimal interference voltage suppression.
Power frequency 50 Hz:
Power frequency 60 Hz:
Operation: Set the number of channels you wish to assign on the input module. If there
are fewer than four channels, the measured values will be updated faster.
Broken wire: Once the broken wire signal has been activated, a break on one of the lines to
the sensor (thermocouple) or of the sensor itself causes the red LED above the
function selection switch to light up. At the same time, the broken wire error bit
F (bit 1, byte 1) for the faulty channel is set.
The module "recognizes" a wire break by applying a conventional tripping current
to the input terminals and by comparing the resulting voltage to a limit value. If
there is a wire break in the sensor or the lines, the voltage exceeds the limit
value and a "wire break" signal is sent.
measured with a digital voltmeter, the tripping current pulses cause apparent
fluctuations of the signal. Deactivation of the wire break signal does not turn off
the tripping current.
Table 15-9. Settings for the Operating Mode Switch for Analog Input Module 464-8MA11
Function
Power supply
frequency
Operation
Wire break
15-44
Integration time 20 ms
Integration time 16.66 ms
Settings for Operating Mode Switch
50 Hz
4
3
2
1
1 channel 2 channels (channel 0
(channel 0) and channel 1)
4
3
2
1
With wire break signal
4
3
2
1
S5-90U/S5-95U
When the signal at the input is
60 Hz
4
3
2
1
4 channels (channel 0
- channel 3)
4
3
2
1
No wire break signal
4
3
2
1
EWA 4NEB 812 6115-02b
4
3
2
1