EMS EMS520 Manual page 6

RCU
The RCU provides instrument control functions, opacity readings, alarms, analog outputs, communications, system information and
more. The color 5x7" viewing screen can be seen in low light levels and bright. The RCU is rated NEMA 4X/IP65 when panel
mounted. Battery backup for all memory is typically 7 years.
o o o
The control unit should be mounted in a control room environment i.e., clean, temperature with max/min of +0 to +50 C (+32 to +
o
122 F). The EMS520 control unit provides instrument control functions, opacity readings, alarm and fault indicators, analog outputs,
and diagnostics with contact closures.
Optional Air Purge Weather Cover System
The transceiver and reflector may be mounted in weather covers. The weather covers are fairly compact to allow movement around
them even on a three-foot walkway or platform. They protect the stack-mounted components from dirt, moisture; stack temperatures
within the specified ambient temperatures limits, and errant air currents around the stack.
The air purge system constantly circulates air past the optical window. The air flow is directed through the hose to an air plenum on
the stack side of the optical window. The air flow in the air plenum area results in reduced pressure and increased velocity. This
venturi effect tends to continually draw the air around the optical window into the purge air stream, thereby keeping the lens clean
for extended periods.
Alignment system
The EMS520 includes a built-in through-the-lens alignment system. The alignment target can be viewed through a window on the
transceiver. Adjustments to changes in alignment are provided by a 3-point alignment system, which is integral to the air plenum.
Cabling to Smart Service Module
Port 2, 6-pin R J25 connector Pin 1 (+), Pin 6 (-). RS-485 cabling may be up to 2000 feet in length. Belden P/N 3106A cable is
recommended. Note: Cable drawing and pin out at the end of drawing section.
OPTIONAL SNAP-IN: The standard cabling used between the RCU and other devises, s at a minimum 6-pair, #20 AWG, twisted,
shielded. Separation distance approximately 1000FT, more pairs or larger gage than 20 AWG is also acceptable.
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