Wiring inputs and outputs
Carrier® ChillerVu™
(OPN-PSM-MPCXPE)
Carrier Proprietary and Confidential
CARRIER CORPORATION ©2017
Installation and Start-up Guide
17
All rights reserved
Inputs
The Carrier® ChillerVu™ and expanders have universal inputs that accept the signal types described below.
Signal Type
Description
Thermistor
1
Precon type 2 (10 kOhm at 77°F). Input voltages should be from 0.489 Vdc to 3.825 Vdc
for thermistors.
Thermistor 5 kOhm at 77°F (25°C)
Dry contact
A 5 Vdc wetting voltage detects contact position, resulting in a 1 mA maximum sense
current when the contacts are closed.
0–5 Vdc
0–10 Vdc
The output impedance of a 0–5 Vdc or a 0–10 Vdc source must not exceed 200 Ohms.
The input impedance of the Carrier® ChillerVu™ is approximately 20 kOhm.
0–20 mA
The input resistance on the positive (+) terminal is 250 Ohms. The
Aux Power Out
connector is capable of supplying 24 Vdc to multiple 4–20 mA transducers, but the total
current demanded must not exceed 200 mA. If the voltage measured from the
Aux Power
Out
connector to
Gnd
is less than 18 Vdc, you need to use an external power supply.
RTD
1
Platinum - 1 kOhm at 32°F (0°C)
Nickel/Iron - 1 kOhm at 70°F (21°C)
Balco TS8000 - 1 kOhm at 70°F (21°C)
Input voltages should be from 0.6–1.2 V
NOTE
For improved accuracy, Carrier recommends using an external current transducer-
type RTD, when RTD's are required with the Carrier® ChillerVu™. Be aware that milliamp-
type sensors require different jumper settings and different wiring arrangements.
Pulse counter
2
Pulse counting up to 40 pulses per second.
Minimum pulse width (on or off time) required for each pulse is 12.5 msec.
1
To use a thermistor or RTD not listed above, you can set up a custom translation table for your sensor.
2
The Carrier® ChillerVu™ can perform pulse counting for dry contact or voltage inputs if you assign the input to a
Pulse to Analog Input microblock.
NOTE
If you have one or more RTD's connected to the inputs, the total current draw of all Thermistor, RTD, and
Dry contact devices wired to the inputs should not exceed 10 mA. Exceeding this limit affects the accuracy of the
RTD's. Use the following approximations as a reference:
•
10 kOhm Thermistor draws approximately 0.334 mA.
•
1 kOhm RTD draws approximately 0.834 mA.
•
Dry contact draws approximately 1 mA.
For example, if using an expander with 12 RTD's connected to the inputs, the remaining 4 inputs cannot be used.
This assumes negligible wiring impedance (<10 Ohms) for each RTD input, with up to 100 feet of 22 AWG cable.
Output wiring specifications
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
