I-O Display Systems Basic I/O Product - Manual (Page 37)

Setup & Installation 2
2-20(Vol.1)
Analog Inputs:
Note: analog modules normally run hot to the touch.
Correct polarity connections are essential to proper operation of all the analog inputs.
Connections to terminals marked with a + must be more positive than the terminals marked
with a -. Thermocouples and RTDs are connected directly to modules with special connectors
which insure correct polarity.
Analog input module status indicators are On dimly, when input modules are installed, wired
correctly, and their input signal is within the module’s valid range. If these conditions are not
met, the indicator light may be on brightly, off or may flicker.
The wiring and operation of analog input modules can be verified by the host issuing a
Configure as Input instruction, setup H, followed by a read input value instruction, Analog L.
See the software protocol manual or quick reference card for instruction details.
Figure 2-10, figure 2-11, and figure 2-12 show the wiring for various types of analog inputs.
With the exception of thermocouples and RTD modules, connections are made via the black
terminal strip. In the case of thermocouples and RTDs mating connectors are included. There
must be nothing connected to the screw terminals corresponding to these module positions.
The source of analog input voltage or current is external to the BASIC I/O with the exception
of ITP590, ITR10, ITR100, and ITR100-1.
Figure 2-10 AC Current and Voltage Wiring.