Table of Contents
Analog Input
The Analog Inputs on the standard boards are grouped by ADC chips with 6 channels each.
Features
| Number of channels ZSOM-Control | 2 chips a 6 channels = 12 channels |
| Number of channels ZSOM-Mini | 1 chip a 6 channels |
| Resolution | 16 bit |
| Range | ±5V or ±10V selectable per chip |
| Sampling rate | up to 450kHz selectable per chip |
| sample and hold | simultaneous per chip |
| Anti aliasing | 4th order with fg=200kHz |
| Maximum input voltage | ±32V |
Connecting a signal
The signal is routed trough the following stages after the screw terminal:
- Impedance converter
- Anti aliasing filter
- Analog to digital converter
Impedance converter
current hardware version ZSOM-Control V1.2ff ZSOM-MINI V1.1ff
hardware versions ZSOM-Control V0 .. V1.1
This schematics shows the first stage of the input circuit of one Analog Input channel.
The input is optimized for low or mid impedance voltage signal sources.
The 243Ohm shunt (R311) is not assembled by default. it can be used to transform th einputs to sense current signals such as 4-20mA norm signals.
To adapt for high impedance signal sources, current sources or other special signal sources, please contact Schmid-Electronik for advice.
Anti aliasing filter
This graph shows the frequency response of the 4th order anti aliasing filter. This characteristic has to be considered if the measured signal consists of frequencies above 100kHz.
Analog to digital conversion
The ADC chips have sample and hold functionality. This means, that all signals in a group of 6 channels per chip are sampled simultaneously at exactly the same time.