Distech Controls ECL/ECB-PTU Series User Manual page 65

Figure 37: Maximum Number of VAVS Devices on a Daisy-Chain at Evenly Spaced Intervals
10
9
8
7
6
5
4
3
2
1
0
100
(30) (45)
Laboratory testing conditions for the above graph are as follows:
• Distance between each VAV is evenly spaced along the entire wire length
• Transformer specification: 100VA (120/24VAC)
• Tested at room temperature with low voltage line conditions: 108VAC (50Hz)
For non-VAV devices, determine the appropriate size transformer for the job as follows:
• Add up the power requirements of all devices plus all external loads (see
Loads on page 61). Multiply the total power needed by a multiplier of 1.3, as a security
margin. For example, to power five devices (15 VA each), the total load is 75 VA multiplied
by 1.3 is 98 VA. Choose a size of transformer just over this amount: For example, a 100
VA model.
• When the total load of a number of devices requires a transformer with a rating greater
than 100 VA, use two or more transformers. Ensure that the load to be connected to each
transformer follows the guideline of Step 1 above.
Always use a separate transformer for each ECL-600 series controller and for each
of its associated I/O Extension Modules. One terminal on the secondary side of each
of these transformers must be connected to the building's ground and to the respec-
tive controller's or I/O Extension Modules' 24V COM terminal. See
Extension Module Power Supply Requirements
Network Guide
Daisy Chain Performance
150 200 250
(60) (75)
Total Wire Length
LonWorks Communication Bus Fundamentals
VAVS + SmartVue (AWG18)
VAVS + SmartVue (AWG16)
VAVS + SmartVue + 2DO (1,6VA each) (AWG18)
VAVS + SmartVue + 2DO (1,6VA each) (AWG16)
VAVS + SmartVue + SmartVue CO2 + 2DO (1,6VA each) (AWG18)
VAVS + SmartVue + SmartVue CO2 + 2DO (1,6VA each) (AWG16)
300 350 400
(90) (105) (120)
Feet
(meters)
on page 66.
450 500
(135) (150)
About External
ECx-4XX I/O
63