Introduction—ASC and N2 Bus Networking and Troubleshooting Guide 5
Installing ASC Controllers
This section explains how to install ASCs. The VAV and UNT100/101
inputs, outputs, and N2 Bus connections require complete isolation from
earth ground.
!
WARNING: Do not earth ground the 24 VAC high side of the
ASC’s transformer or any of the ASC’s “BO”
terminals. If you do, you will damage all of the
interface components that are connected, including
the Cable Pro, laptop PC, Companion PC, and
MM-CVT101.
In some cases, earth grounding the common side of the AHUs, LCPs, or
UNT110/111s is allowed, because only one earth ground can exist per
ASC. Use these procedures to ensure proper isolation. Test the:
●
field device wiring for proper isolation
●
transformer for isolation and correct polarity termination
●
connected field devices, transformer, and ASC for proper isolation
●
transformer and ASC for proper VA load requirements
Obtain the following tools to perform the installation:
●
Digital Multimeter (DMM)
●
100K ohm resistor, 1/4-watt
●
Double banana plug (optional; shown in Figure 1; available from local
electronics store or ITT Pomona Stock No. 34F856 or 34F845)
100K ohm, 1/4-watt
BANANA
Use double banana plug for all tests that require
a 100K ohm resistor placed in parallel with DMM.
Steps:
1. Connect 100K ohm resistor under plug's prongs.
2. Insert banana plug into DMM.
3. Connect leads of DMM into banana plug.
Figure 1: Double Banana Plug Used with 100K Ohm Resistor
Tools Required
Summary of Contents for METASYS ASC
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