6. Cal LED—Illuminated while the controller is in the
calibrate mode.
NOTE
In the Setpoint Display or Setpoint Adjust mode,
a flashing alarm LED identifies the particular set-
point currently being indicated on the digital dis-
play. A flashing Cal LED indicates that the pro-
grammed calibration gas concentration in % LFL
is currently being shown on the digital display.
7. Fault LED—Flashes upon detection of a system
fault and is on steady during the power-up time
delay.
8. Reset Pushbutton—Used for various system pro-
gramming and calibration functions as well as for
resetting the controller.
9. Set Pushbutton—Used for various system pro-
gramming and calibration functions.
Setpoints
The R8471 Controller has independent Low, High,
and Auxiliary alarm setpoints, with corresponding out-
puts.
The programmed calibration gas concentration in %
LFL is also displayed and adjusted with the alarm set-
points. This value must be equal to the % LFL con-
centration of the calibration mixture that is used for
the span adjustment.
The adjustment range is:
Low alarm 5 to 50% LFL
High alarm 10 to 60% LFL
Auxiliary alarm 5 to 90% LFL
Calibration gas 30 to 99% LFL.
The alarm setpoints and calibration gas concentration
can be checked by pressing the Reset pushbutton
located on the front panel of the controller. See
“Setpoint Adjustment” and “Calibration” sections.
Outputs
The R8471 Controller is available in a Base version
and a Premium version. The differences between the
two models are the output configuration and program-
ming options.
Base Model—The base controller is furnished with
open collector transistor outputs (rated 100 ma at 32
volts dc) for the Low alarm, High alarm, Auxiliary
alarm, and Fault circuits. The normally de-energized
alarm outputs are energized when their correspond-
ing setpoints are exceeded. The fault output is nor-
mally energized and becomes de-energized upon
detection of a system fault.
Premium Model—The premium model is furnished
with a set of four relays in place of the four solid state
outputs. The relays have SPST contacts rated 5
amperes at 30 vdc or 250 vac.
This model also includes a selectable isolated/non-
isolated 4 to 20 ma dc current output for transmitting
system information to other monitoring devices. The
linear 4 to 20 ma output corresponds to levels from 0
to 100% LFL. If a system fault is detected, the output
drops to less than 1.0 ma. The current output can be
calibrated in the field to ensure maximum accuracy.
(Refer to the “Calibration” section for details.)
Programming Options (Premium model only)—Each of
the four relays is field selectable for either normally
open or normally closed contacts using jumper plugs
located on the printed circuit board inside the con-
troller. (See Table 1.)
The alarm relays are also switch programmable for
either normally energized or normally de-energized
operation. The fault relay is normally energized.
The low and auxiliary alarm relays are programmable
for either latching or non-latching operation. The high
alarm relay is always latching and the Fault relay is
non-latching. Latching relays are reset using either
the Reset pushbutton on the front panel of the con-
troller or an external reset switch.
The 4 to 20 ma circuit is selectable for isolated or
non-isolated operation.
Automatic Diagnostics and Fault Identification
The microprocessor based controller features self-
testing circuitry that continuously checks for faulty
sensor or open sensor wiring, low or high input volt-
age, and other problems that could prevent proper
system response. When power is applied, the micro-
processor automatically tests memory. In the Normal
operating mode, it continuously monitors the input
signal from the transmitter to ensure proper function-
ing. In addition, a “watchdog” timer is maintained to
ensure that the program is running correctly. If a fault
should occur:
— The Fault LED flashes.
— The digital display identifies the nature of the fault
using an alpha-numeric code. Refer to Table 2.
— The normally energized Fault output is de-ener-
gized.
— The dc current output drops to less than 1 ma.
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