Problems and their possible solutions - HPP272

HPP272 User Guide

Document code
M211972EN
Revision
G
Language
English
Product
HPP272
Document type
User guide

If you have a problem with using the probe, check the following tables before contacting Vaisala. If the problem you have is not listed in the tables, or if the proposed solution does not fix the problem, contact Vaisala technical support.

You can check the probe diagnostics and status with the Insight software and Modbus status registers (see Status registers).

Response time is slower than specified

Problem: Response time is slower than specified.
Possible cause: Solution:
The filter is blocked.

Change the filter.

Be careful not to touch the sensors when the filter is off the probe.

The probe has fallen and the filter has hit the floor.

Remove the filter and visually check the sensors.

  • If the sensors are bent, broken, or disconnected, contact Vaisala technical support.
  • If the sensors are intact, change the filter. The filter is made of porous material, and if the filter hits the floor, the filter material may get pressed and become less permeable. This reduces the rate at which air flows in and out of the filter, directly affecting the measurement.

Be careful not to touch the sensors when the filter is off the probe.

The probe has been exposed to unsuitable chemicals (for example, DMSO).

Change the filter and perform a sensor purge.

Be careful not to touch the sensors when the filter is off the probe.

The measurement filtering factor is configured to be too slow.

Use the Vaisala Insight software, Modbus configuration register 030Ahex, or an Indigo200 transmitter to disable the filtering factor (set filtering factor to "1"), and check the measurement again. See:

The ambient temperature has changed quickly, which may result in a slower change in RH reading.

No actions required.

H2O2 or humidity reading does not change during regular use for less than 5 minutes

Problem: H2O2 or humidity reading does not change during regular use for less than 5 minutes.
Possible cause: Solution:
Purge is being performed (duration of the purge is 4 minutes). No actions required.

H2O2 or humidity reading does not change during regular use for more than 5 minutes.

Problem: H2O2 or humidity reading does not change during regular use for more than 5 minutes.
Possible cause: Solution:
In analog mode: The scaling of the output is unsuitable, preventing the change from showing. Check and change the analog output scaling with Insight software (see Vaisala Insight PC software).
In analog mode: The error level is configured within the measurement output level, and the probe is in error state. Check the probe diagnostics with the Insight software (see Vaisala Insight PC software).

Consider changing the analog output error level to be outside the measurement scale.

Measurement reading appears incorrect

Problem: Measurement reading appears incorrect.
Possible cause: Solution:
The temperature probe is installed near a heat source or too close to the H2O2 and humidity probe. Change the location of temperature probe. See Installation for recommended installation locations.
The filter is wet.

Remove the filter, pour out any water, and let the filter dry. Depending on air humidity and temperature, drying the filter in ambient air can take from a few hours to a day. Alternatively, you can dry the removed filter with nitrogen gas or dry pressurized air. When the filter is dry, reinstall the filter.

Be careful not to touch the sensors when the filter is off the probe.

Perform a sensor purge.

The filter is blocked or dirty.

Change the filter.

Be careful not to touch the sensors when the filter is off the probe.

Condensation has formed on the sensor when the probe was powered off.

When the probe is powered off, exposure to H2O2 condensation can cause the PEROXCAP sensor to fail within a day, and the sensor will not recover. When the probe is powered on, the heated sensor withstands condensing H2O2 conditions.

A sensor damaged with H2O2 condensation during power-off time cannot be repaired.

The filter is not installed on the probe. Do not use the probe without the filter. Install the filter on the probe.
The yellow transport cap is still on the probe. Remove the yellow transport cap when measuring with the probe.
The filter is broken.

Do not use the probe if the filter is broken. Remove the filter and visually check the sensors:

  • If the sensors are bent, broken, or disconnected, contact Vaisala technical support.
  • If the sensors are intact, change the filter.

Be careful not to touch the sensors when the filter is off the probe.

In analog mode: Maximum load has been exceeded. Check the analog output load, and reduce it to the specified maximum load or less. See output specifications for the permitted maximum load.
Ambient pressure is not normal atmospheric pressure. Check the ambient pressure. See operating environment specification for the permitted operating pressure.
The PEROXCAP sensor is at the end of its life cycle. Check the sensor vitality information in the Insight PC software diagnostics view. See Sensor vitality information in Insight.

H2O2 concentration reading shows > 0 ppm even though the probe is not exposed to H2O2

Problem: H2O2 concentration reading shows > 0 ppm even though the probe is not exposed to H2O2.
Possible cause: Solution:
Normal variation due to a slight difference in behavior between the two humidity sensors. No actions required.
If the reading remains > 0 ppm for 2 ... 10 hours, H2O2 concentration has drifted. The intelligent measurement algorithm can correct errors of < 30 ppm by itself when the probe is not exposed to H2O2. Keep the probe powered on for a few hours in a stable temperature and RH, not exposed to H2O2.

The filter is wet

Problem: The filter is wet.
Possible cause: Solution:
Sprayed water has entered the filter when cleaning the probe.

Remove the filter, pour out any water, and let the filter dry. Depending on air humidity and temperature, drying the filter in ambient air can take from a few hours to a day. Alternatively, you can dry the removed filter with nitrogen gas or dry pressurized air. When the filter is dry, reinstall the filter.

Be careful not to touch the sensors when the filter is off the probe.

Perform a sensor purge.

The filter is broken

Problem: The filter is broken.
Possible cause: Solution:
The probe has fallen or an object has hit the filter.

Do not use the probe if the filter is broken. Remove the filter and visually check the sensors:

  • If the sensors are bent, broken, or disconnected, contact Vaisala technical support.
  • If the sensors are intact, change the filter.

Be careful not to touch the sensors when the filter is off the probe.

The probe does not power on, or there is no communication from the probe after power-on

Problem: The probe does not power on, or there is no communication from the probe after power-on.
Possible cause: Solution:
Power input to the probe is off. Turn on the power input to the probe.
Probe wiring is incorrect. Check the probe wiring and correct it if needed. See Wiring.
The probe cable is not properly connected. Check the cable connection and correct it if needed.
The operating voltage is incorrect. Check the operating voltage and correct if needed. See input and output specifications for the correct voltage.
In digital mode: The communication settings (for example the device address) are incorrect either in the probe or in the system where the probe is connected.

Check the communication settings. You can check the probe's communication settings with the Insight software. See Vaisala Insight PC software

Insight PC software resets repeatedly (reset loop) and cannot be started

Problem: Insight PC software becomes stuck in a reset loop at start-up
Possible cause: Solution:
Insight SW version 1.0.2.76 can become stuck in a reset loop when using the ATEST output test selections or in certain sensor error states. Uninstall Insight SW version 1.0.2.76 and install either an older or newer Insight SW version. See www.vaisala.com/insight for the latest Insight SW release, or contact Vaisala Support for earlier SW versions.

In analog mode, there is no output signal (signal level is 0 mA)

Problem: In analog mode, there is no output signal (signal level is 0 mA).
Possible cause: Solution:
Pin #5 was floating at start-up or reset, which means the probe is in digital mode. Check pin #5. See Wiring.
Analog outputs are configured to be off.

Check the analog output mode with the Insight software or Modbus configuration registers 0700hex and 0800hex. See:

Probe wiring is incorrect. Check the probe wiring and correct it if needed. See Wiring.
The operating voltage is incorrect. Check the operating voltage and correct if needed. See input and output specifications for the correct voltage.
The probe cable is not properly connected. Check the cable connection and correct it if needed.
Power input to the probe is off. Turn on the power input.
The analog output error level is configured to be 0 mA, and the probe is performing start-up purge or is in error state. Wait for 5 minutes for the possible start-up purge to finish. If the output remains 0 mA after 5 minutes, check the probe diagnostics with the Insight software (see Vaisala Insight PC software).

Triggering manual purge with Modbus cannot be completed successfully

Problem: Triggering manual purge with Modbus (register 1283/0502hex) cannot be completed successfully.
Possible cause: Solution:
A value is written into the register before the purge has completed.

The manual purge trigger register must only be written into once per purge cycle (write 1 into the register to start the purge). After starting the purge by writing 1, the register value must only be read until the purge cycle has completed.

Write into and read from the register in the following order:
  1. Write 1 to start the purge
  2. Read the updating progress value (1100 %)
  3. When the progress has reached 100 %, the value of the register changes either to 0 (purge completed successfully, purge not in progress) or -1 (purge failed, purge not in progress)
  4. After reading the final value (0 or -1), a new purge can again be triggered by writing 1.

In analog mode, start-up purge is not performed

Problem: In analog mode, start-up purge is not performed.
Possible cause: Solution:
The probe is in digital mode at start-up (pin #5 is floating). Check pin #5. See Wiring.

At start-up in analog mode, the probe remains in the error state for over 5 minutes

Problem: At start-up in analog mode, the probe remains in the error state for over 5 minutes.
Possible cause: Solution:
The analog output scaling is unsuitable. For example, the scale 0 ... 5 %RH is too narrow compared to the full measurement scale of RH. Check the analog output scaling with the Insight software and correct the scaling if needed (see Vaisala Insight PC software).
There is a probe or sensor error. Check the probe diagnostics with the Insight software (see Vaisala Insight PC software).