Distech Controls IO-R-16 Wiring Manual page 3

Preparation
Voltage drop considerations
You should be aware of potential voltage drops in the connecting "trunk power" cabling. Typically, this applies only
if modules are located in different locations—that is, not near the power supply.
Note that each IO-R-16 draws (at most, when all four relays are pulled in) 0.133A, and thus can introduce voltage
drop when long cabling distances are used for power/backup.
consumption for these purposes.
Table 2 IO-R-16 Power Consumption.
Max per
Device
System
IO-R-16 see Table 1
Undersized selection of power cabling can result in unacceptably high voltage drops, and remotely located IO-R-16
modules may not operate correctly—especially during emergency (battery backup) operation.
The maximum allowable voltage drop due to wiring is 1.5V.
measured across the P+ and P- at the source power supply, and the P+ and P- at the furthest expansion module
(IO-R-16). Table 3 provides a voltage drop chart, showing voltage drops per 100 feet of paired wire of different
gauges (AWG), at different load amps.
Table 3 Voltage Drop Per 100 Feet Run (30m) of Paired Wire.
Gauge
(AWG)
0.10A
10
0.020
12
0.032
14
0.050
16
0.080
18
0.127
20
0.202
22
0.320
For an example, consider a system where two IO-R-16 modules are mounted remotely in a location 500 feet (152m)
away. In this example, worst-case amps used by each remote IO-R-16 is 0.133A. Looking at
column, a #16 AWG cable pair drops 0.20V per 100 feet, meaning a 500 foot run would drop 1V. This would be a
good choice over an #18 AWG cable, which would drop 1.6V (above the 1.5V maximum allowable drop).
Preparation
Unpack the IO-R-16 module and inspect the contents of the package for damaged or missing components. If
damaged, notify the appropriate carrier at once, and return for immediate replacement (see
Unit," page 18). See the next sections
Remote IO-R-16 Module Mounting and Wiring Guide
Amps / W used
@ 15Vdc (each)
0.133 A / 2.00 W
0.25A 0.5A
0.05 0.10
0.08 0.16
0.13 0.25
0.20 0.40
0.32 0.64
0.50 1.01
0.80 1.60
"Included in this Package"
Table 2 provides a summary of IO-R-16 power
Notes
Has 4 on-board relays.
This equates to the difference in voltage
Load Current
1.0A 1.5A
0.20 0.30
0.32 0.48
0.50 0.75
0.80 1.20
1.27 1.91
2.02 3.03
3.20 4.80
and "Material and Tools
August 2, 2017
Preparation
2.0A 4.0A
0.40 0.80
0.64 1.27
1.01 2.02
1.60 3.20
2.54 5.08
4.03 8.07
6.40 12.81
Table 3 at the 0.25A
"Returning a Defective
Required".
3