Measurement Computing DataShuttle - Manual (Page 111)

DataShuttle and DynaRes 11-12-01 Analog Input & Output 13-11
Figure 13-6. Current Connections
High Voltage Divider
Our data acquisition boards and terminal panels are limited to measuring voltage up to 10 Volts directly.
Although this is sufficient for most sensors, provision has been made for measuring voltages up to ±150
Volts.
Figure 13-7 shows the connections for high voltage measurement. R3 and R1 are used as a voltage divider.
Do not connect voltages higher than 150 Volts into the terminal panel or you risk arcing between the circuit
board traces. Observe the power rating of the resistor you install at R1. Space is provided for a ¼ Watt
resistor. To measure 150 Volts it can be no smaller than 100k ohms.
One side of the analog input should be connected to ground to minimize the common mode voltage. In all
cases the common mode voltage must be kept within the specifications of the board (refer to the user
manual that accompanies the board).
Figure 13-7. High Voltage Connections
Voltage Output
Voltage outputs can drive a variety of controllers, amplifiers, and other devices. Figure 13-8a shows
typical connections for voltage output.
The voltage output is on the “+” terminal. The negative terminal of the driven devices is returned to the “-“
terminal of the same channel. This is the ground for the computer. By using the “-“ terminal, maximum
precision is achieved. Although the “COM” terminal is also ground, it may have small variations induced
by other channels or by digital signals. Notice that the load is not connected to ground except by the “-“
return wire. This is a normal situation.