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Operation Manual HORIBA APDA-371
Particulate Monitor
Date:
April, 2010
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HORIBA Europe GmbH, Julius-Kronenberg-Str. 9, D-42799 Leichlingen,
: +49(0)2175-8978-0,
: +49(0)2175-8978-50
Page 40
failures even when connected to a UPS, contact HORIBA for instructions on possible upgrades. This error also causes
the digital concentration value to go full-scale.
R
REFERENCE MEMBRANE:
This error indicates that the reference membrane assembly is not physically
extending and retracting properly. The error is generated if photo sensors S2 and S3 never change state despite drive
commands to the membrane motor, and a timeout of the membrane motion occurred after 15 seconds.
N
NOZZLE STUCK TIMEOUT (or Delta-T exceeded):
This error indicates that the nozzle motor is not
operating. The error is triggered if photo sensors S4 and S5 never change state despite drive commands to nozzle
motor, and if the sensors do not see the nozzle motor move within 12 seconds of it being turned on. NOTE: The nozzle
motor lifts the nozzle, but the nozzle is lowered only by its spring. So it is possible for the nozzle to become stuck in the
UP position without generating an error! Proper maintenance and inlet alignment prevents this.
The “N” error is also used to indicate that the Delta-Temperature set-point was exceeded. This occurs if the sample air
temperature (measured below the filter tape) is hotter than the ambient air by at least one degree above the set-point
value. This is due to the normal heating of the sample air by the smart heater. In this case, the error is used to simply
flag the data. Frequent errors may indicate that the set-point is set too low. In most applications Delta-T control is
disabled entirely. See the inlet heater settings instructions in this manual.
F
FLOW ERROR:
This error occurs if the average air flow over the sample period was out of the limits set
by the FRl (low limit) and FRh (high limit) values. The error will also be generated if the flow during any part of the
sample period goes out of regulation by more than 5% for more than 5 minutes, or by more than 10% for more than 1
minute. In the later case, the sample is stopped as well. Momentary changes in airflow do not usually trigger the error.
This error may begin to occur if the vacuum pump is wearing out, if the muffler is clogged, or due to a fault with the flow
sensor, flow controller, or air tubing.
The “F” error is also used to indicate if the ambient temperature or barometric pressure sensor has failed or is
incorrectly connected (only if the APDA is set for ACTUAL flow or concentration reporting). This applies to auto ID
sensors BX-592 and BX-596, the internal filter pressure sensor, and CARB style temperature sensors. The sensor is
considered failed if any 1 minute average reading of the sensor is at or beyond the min or max measurement range of
the particular sensor.
P
PRESSURE DROP EXCESSIVE:
This error indicates that the vacuum beneath the filter tape has
exceeded the limit set by the AP value. This is almost always caused by high concentrations, or certain types of
particulate clogging the filter tape. When this error occurs, the APDA stops the pump to prevent overheating, completes
the measurement early, then waits for the top of the next hour. To increase the amount of particulate which can build up
on the tape before this occurs, set the AP value higher.
D
DEVIANT MEMBRANE DENSITY:
This error indicates that the reference membrane span check
measurement (m) for that hour was out of agreement with the expected value (ABS) by more than ±5%. If these errors
start to occur regularly, it could indicate that the beta detector is beginning to wear out. It can also be caused by a dirty
or damaged membrane, or by a membrane assembly that is not extending or retracting fully. Also sometimes called a
APDA CAL error.
C
COUNT ERROR:
This error indicates that the beta particle counting system is not operating properly, and
is activated if the beta count rate falls below 10,000 per 4 minutes. The beta count rate through clean filter tape is
usually more than 800,000 per 4 minutes. This error could occur if the beta detector has failed or if something is
blocking the beta particles, such as a stuck membrane assembly or debris.
T
TAPE BREAK: This error indicates that the filter tape is broken or has run out. The error is triggered if photo
sensor S6 is ON continuously, despite drive commands to motors M3-M5. Tape supply motor (M3) and tape take-up
motor (M4) time out after 10 seconds. Capstan motor (M5) times out after 6 seconds. This error is also generated if the
pinch roller assembly has been left latched in the UP position when a measurement cycle starts. Photo sensor S9 is ON
any time the latch is set. The APDA-371 has no way of unlatching and lowering the pinch rollers. It must be done
manually. A tape-break error will cause the measurement cycle will stop, and the APDA to repeat the last good
concentration value until the filter tape is fixed or replaced.