guidelines for determining proper wire sizes and cable
lengths.
In addition to the wiring guidelines in Table 5, observe the
following guidelines when wiring CVM inputs and outputs:
• Run all low-voltage wiring and cables separate from
high-voltage wiring.
• All input and output cables, regardless of wire size or
number of wires, must consist of twisted, insulated, and
stranded copper wires.
• Shielded cable is not required for input or output cables
but is recommended for input and output cables that
are exposed to high electromagnetic or radio frequency
noise.
• Cable runs of less than 30 m (100 ft) often do not
require an offset in the input/output software setup.
• Cable runs over 30 m (100 ft) often require an offset in
the input/output software setup.
I/O terminal blocks, ratings and requirements
Table 5: I/O terminal blocks, functions, ratings, requirements, and cables
Terminal Block label
Terminal labels Function, ratings, and requirements
To determine wire size and
maximum cable length
+15 V
15 VDC Power Source
for active (3-wire) input
devices connected to the Universal UI-n terminals.
Provides 35 mA total current.
Same as (Universal)
UI-n
.
Note:
Use 3-wire cable for
devices that source power
from the +15 V terminal.
Analog Input - Voltage Mode (0–10 VDC)
10 VDC maximum input voltage
Internal 75k ohm Pulldown
See Guideline A in Table 6.
Analog Input - Resistive Mode (0–600k ohm)
Internal 12 V, 15k ohm pull up
Qualified Sensors: 0–2k potentiometer
RTD (1k Nickel [Johnson Controls sensor]
1k Platinum, and A99B Silicon Temperature Sensor)
Negative Temperature Coefficient (NTC) Sensor
10K Type L (10K Johnson Controls Type II is
equivalent to Type L) or 2.252K Type II
See Guideline A in Table 6.
UI-n
Binary Input - Dry Contact Maintained Mode
1 second minimum pulse width
Internal 12 V, 15k ohm pull up
See Guideline A in Table 6.
UNIVERSAL
(Inputs)
UI-C
Universal Input Common
for all Universal IN
terminals
Note:
All Universal UI-C terminals are
isolated from all other commons.
Same as (Universal)
UI-n
.
M4-CVM VAV Box Controllers Installation Guide
7
