Trane RTWA 70-125 TON - Manual (Page 72)

72 RLC-SVD03A-EN
Module Power and Miscellaneous I/O
Compressor Module (MCSP) (1U4 AND 1U5)
ƽ WARNING
Live Electrical Components!
During installation, testing, servicing and troubleshooting of this
product, it may be necessary to work with live electrical
components. Have a qualified licensed electrician or other
individual who has been properly trained in handling live
electrical components perform these tasks. Failure to follow all
electrical safety precautions when exposed to live electrical
components could result in death or serious injury.
Test Points
There are two test points associated with the MCSP module. They are easily
read with a DC voltmeter by probing the PC board solder pads found in the
upper left hand corner of the module. The positive meter lead should be
connected to the pad while referencing the negative meter lead to the board
edge ground plane.
NOTE: Don't use the aluminum module enclosure as a reference as it
has an anodized surface with insulating properties.
The DC voltage shall be within the tolerance specified below. If not replace
the module.
TP1: +5 volts DC ±5%
TP2: +12 volts DC ±5%
IPC Address Switch SW1
Refer to
Troubleshooting Modules Using IPC Diagnostics on page 9 .
Current Gain (or Overload) Dip Switch SW2
The Compressor phase current inputs on the individual MCSP modules are
“normalized” thru the proper setting on this switch. The term “Compressor
Current Overload setting” is actually a misnomer. Instead the setting should
be thought of as an internal software gain that normalizes the currents to a %
RLA for a given CT and compressor rating. The true nominal steady state
overload setting is fixed at 132%.
The setting of the dip switch SW2 on each of the MCSP modules should
match those of
Table 18 for each compressor. Switch position SW2-1 is the
Most Significant Bit. The decimal equivalent of this setting should also be
verified in the Service Settings Menu, in the CLD display. If the programmed
value does not agree with the dip switch setting for each of the MCSP's, an
informational diagnostic will result. The compressors will be allowed to run,
but default settings (the most sensitive possible) will be used for the internal
software compressor current gains. Refer to Section 7 Current Transformer
and Current Input Checkout for more details.