Data Translation DT9820 Series, Getting Started Manual

Page: 52 / 76

Chapter 6
44
Figure 8 shows how to connect a current loop input (channel 0, in this
case) to a DT9820 Series function module.
Figure 8: Connecting Current Inputs (Shown for Subsystem 0)
Note: If you are using current loop inputs, set up the software so
that bias return resistance is used. For more information, refer to
Chapter 4 starting on page 21 .
TB1, 1
TB1, 3
.
.
.
TB1, 2
Analog Input 0
Analog Input 0 Return
Analog Ground
4 to 20 mA
+V
CC
User-installed
resistor
The user-installed resistor connects the high side of the channel
to the low side of the corresponding channel, thereby acting as a
shunt. If, for example, you add a 250
Ω
resistor, then connect a 4
to 20 mA current loop input to channel 0, the input range is
converted to 1 to 5 V.
It is recommended that you software-select 10 k
Ω
of termination
resistance to connect the low side of channel 0 to analog ground
(a physical resistor is not required). Refer to
page 21 for more
information.
STP9820 Screw Terminal Panel