Carrier RTU OPEN 11-808-427-01 - Manual (Page 20)

Installation
14 RTU Open
Inputs
These RTU Open inputs accept the following signal types:
These
inputs...
Support this
signal type... Description
1, 2 4-20 mA The input resistance on the positive (+) terminal is 250 Ohms.
The Aux Power Out terminal is capable of supplying 24 Vdc to
a 4-20 mA transducer, but the total current demanded must
not exceed 40 mA. If the voltage measured from the Aux
Power Out terminal to Gnd is less than 18 Vdc, you need to
use an external power supply.
3, 5, 8, 9 Binary (24 Vac) 24 Vac voltage, resulting in a 25 mA maximum sense current
when the contacts are closed
6, 7, 10 Thermistor 10 kOhm at 77° F
11 100k Potentiometer Typically used for 33CZT56SPT Setpoint Offset Potentiometer
Binary outputs
The RTU Open has 8 binary outputs. You can connect each output to a maximum of 24 Vac/Vdc. Each output
is a dry contact rated at 3 A, 24 V maximum, and is normally open.
To size output wiring, consider the following:
•
Total loop distance from the power supply to the controller, and then to the controlled device
NOTE
Include the total distance of actual wire. For 2-conductor wires, this is twice the cable length.
• Acceptable voltage drop in the wire from the controller to the controlled device
• Resistance (Ohms) of the chosen wire gauge
• Maximum current (Amps) the controlled device requires to operate
Analog output
The RTU Open has 1 analog output that supports voltage or current devices. The controlled device must share
the same ground as the controller and have input impedance of 500 Ohms maximum for the 4-20 mA mode
on AO - 1.
To wire inputs and outputs
1
Turn off the RTU Open's power.
2 Connect the input wiring to the screw terminals on the RTU Open.
3
Turn on the RTU Open's power.