The OP5340-1 module provides 16 differential analog input channels, sampled at up to 400 kS/s, for measuring ±20V input signals.

An 8-channel version of the module previously available, the OP5340-2, is now discontinued.

Main Features

• 16 analog input channels
• 16-bit resolution
• Simultaneous sampling at 400 kS/s
• Voltage range ±20V
• Factory-calibrated

Channel description

The OP5340-1 module uses eight 16-bit dual-channel analog to digital converters. The figure below represents a simplified schematic of one channel. It is composed of three stages:

• the first stage consists of one operational amplifier that works in differential input mode and allows gain adjustment; 
• the second stage, the level shifter, adapts the signal for the A/D converter input; 
• the third stage consists of the conversion by the A/D converter of the input signal into a digital signal which is transferred via the carrier board to the FPGA chip of the real-time simulator.

Voltage range

The default voltage range is ±20V. This value is obtained by using two resistor values, R1 and R2, to form the input stage :

The Vout value at the output of the amplifier is then obtained by the formula : 

In order to keep the Vout range at ±1 V,  which maximizes the precision of the measurement, the resistor values are set to R1 = 499 kΩ and R2 = 25 kΩ :

The channel gain obtained with the default R1, R2 values is thus 1/20 :

Calibration

• The card is factory-calibrated to ensure accurate output values with a maximum of ±20 mV absolute error on noise and offset.