YZ Systems, Inc. • 3101 Pollok Drive • Conroe, Texas • USA • 77303 • P: 936.788.5593 • F: 936.788.5720
Page 85
NJEX 8300 ver.092001 ATEX Rev.
SSSSS
ECTION
ECTION
ECTION
ECTION
ECTION
13:
13:
13:
13:
13: 8300 S
8300 S
8300 S
8300 S
8300 S
Y
YY
Y
YSTEM
STEM
STEM
STEM
STEM
TTTTT
R
RR
R
ROUBLESHOO
OUBLESHOO
OUBLESHOO
OUBLESHOO
OUBLESHOOTING
TING
TING
TING
TING
2. If problem can not be resolved at this point contact
YZ Systems Technical Service.
Signal Alarm
• The
Loss / Signal
alarm will be active only in the
Analog Proportional-To-Flow
mode. It indicates that
the flow signal voltage has dropped below .5VDC. A
correct flow signal should never drop below 1VDC.
•
Over Flow >125%
is an indication that the flow signal
is showing greater than 125% of the maximum gas
flow according to the set up conditions indicated in the
parameter and calibration sections of the controller.
Non-Alarm Signal Indicators
•
Low Flow
indicates that the flow, as indicated by the flow
signal, has dropped to or below a level as indicated by
the Low Flow Shutoff default parameter in the controller.
•
Over Flow >110%
is an indication that the flow signal
is showing greater than 110% and less than 125% of
maximum gas flow according to the set up conditions
indicated in the Parameter and Calibration sections of
the N-300 controller
•
No Flow
is an indication that the flow signal being
recieved by the NJEX System currently reads a no
flow situation in the pipeline and therefore no odorant
is currently being injected. Odorization will automati-
cally resume when the flow signal indicates flow in the
pipeline.
•
Low Flow Shut Off
is an indication that the flow
signal being recieved by the odorizer, indicates that
present flow in the pipeline is less than the set value
for the Low Flow shut Off set in the in the Parameter
section of the N-300G . When the flow rate drops
below this value odorant injection stops and therefore
no odorization is presently occuring. Odorization will
automatically resume when the flow signal returns to a
level above the set point to stop odorization.
Signal Alarm & Non-Alarm
Troubleshooting Steps
1. The
Loss of Flow
alarm will only be active with a
Linear or Non-linear Analog signal. This alarm will
be activated any time the flow signal goes com-
pletely away or drops below .5v
(2Ma)
. Should this
alarm occur check the flow signal on
TB-1
pins
2
and
3
. Be certain the flow signal is connected to
TB-1
, via the ten pin connector at pins
2
and
3
. If
the signal is above .5v
(2Ma)
, check your grounding
system. If it is .5v
(2Ma)
or less, repair the flow
signal source or cable as required.
2. The
Overflow
alarm will be indicated when the flow
signal indicates 125% of the indicated span set
point.
a. If reading an analog flow signal, linear or non-
linear), a grounding reference error can cause
this condition. Check that the grounding system
is correctly in place. Read the flow signal
voltage on
TB-1
pins
2
and
3
. If the voltage
reading on the volt meter is greater than 5v, the
problem resides with the transmitted signal.
Correct as necessary at the signal source. If
the voltage on the volt meter is within the 1-5v
range, the problem is most likely a grounding or
isolation issue. This can be corrected by re-
establishing the ground or installing a signal
isolator device.
b. If the NJEX System is set to recieve a pulse
signal and this alarm activates, two issues could
generate this alarm. First, the span frequency
could be set incorrectly. Recalculate the span
frequency and inspect the setting in the Calibra-
tion section of the N-300 Controller. The other
cause could be the result of electrical noise
interferance resulting in the system intrepreing
this noise as pulses.
c. If it is believed this is in error or the situation
continues to reoccur, the flow signal calibra-
tions, and parameters should be re-calibrated
with corrected values.