Johnson Controls METASYS ASC, Networking And Troubleshooting Manual

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24 Introduction—ASC and N2 Bus Networking and Troubleshooting Guide
Table 5: Troubleshooting
Symptom Possible Cause Action
N2 Bus is
offline. EOL jumpers and/or W3 jumper on
MM-CVT101 or Companion
Panel/
LTD are not installed.
Install EOL jumpers and W3 jumper
properly.
MM-CVT101 is not plugged into
PC or 120 VAC source. Plug MM-CVT101 into PC or plug it
into a 120 VAC source.
N2 Bus polarity is incorrect. Re-wire N2 Bus wires for proper
polarity.
AHU continually
resets. An AI point greater than 10 VDC is
connected to the AHU102. Disconnect the AI or insert the
“current” jumper.
ASC cycles
online and
offline. A read-only point is defined in the
Companion data base as a
read/write point (AO or BO). Delete the AO or BO point and read
it as an AI or BI point to the
Companion data base.
A Companion process is using an
unconfigured point (i.e., not listed
in HVACPRO.SYM file). Delete the use of the unconfigured
point in the Companion process.
Two or more ASCs have the same
address. Change each duplicate ASC
address to a unique number.
AO and BO
points on the
UNT-111 are not
communicating. The UNT111 was downloaded as
a UNT110. Re-download the UNT, this time
specifying it as a UNT111.
UNT is offline. Points BO-9 and BO-10 are
defined in the UNT data base. Delete the use of BO-9 and BO-10
from the data base.
UNT100/101 or
VAV is offline. The UNT100/101 or VAV is
grounded through the Companion
PC or through another
UNT100/101 or VAV. Disconnect the ground between the
devices.
ASC does not
come online. Two or more ASCs have the same
address. Change each duplicate ASC
address to a unique number.
The address of the ASC was
changed without its power being
cycled afterward. Cycle power on the ASC.
The ten minute delay after
downloading the ASC has not yet
expired (HVAC PRO

Release
1.0 or earlier).
Wait until the delay expires or cycle
power.
Troubleshooting
Chart