Automatic sampling systems are simple, safe and accurate ways to manage representative sampling in your plant. But even the most reliable sampling solution will need ongoing maintenance and service. When your automatic samplers aren’t functioning properly, these troubleshooting tips can keep your system running smoothly.
Automatic samplers are popular choices because they allow a composite sample to be collected from the process by taking smaller, incremental, representative samples of the lot. Automatic sampling ensures a sample can be easily and safely obtained with no need for direct human interface or interference. This safeguards the sample integrity as well as operator safety.
But even the most reliable sampling solution needs ongoing maintenance and service. Troubleshooting should be a part of your regular maintenance plan. When your automatic samplers aren’t working as expected, knowing a few troubleshooting tips can keep your system running smoothly.
Troubleshooting your AUTOMATIC samplers
RX Automatics Samplers
The Sentry Model RX automatic sampler functions by extending a sampling tube into the process line through a solenoid-controlled air cylinder. While in line, the tube is continually taking a dry, free-flowing sample and simultaneously discharging it to the collection point.
| Problem |
Solution |
| There's no sample |
- Verify there is 60-100 PSI air pressure to the cylinder. If not, increase the air pressure to match this range.
- Verify the SBC settings, solenoid valve or DCS.
- Check that the sample tube is stroking.
- Adjust the drive arm weldment. If it isn’t gripping the tube, tighten the set screws.
- Check the sample tube aperture orientation so the tube can rotate.
- Check if the process line is full and aperture exposed.
|
| The sampler is leaking |
- Check the seals and spacers. Replace them if they look worn.
- Check the sample tube.
- If the black QPQ coating or the brass colored NEDOX coating is faded, the sample tube should also be replaced.
|
| The sample tube won't extend or retract |
- Verify there is 60-100 PSI air pressure to the cylinder. If not, increase the air pressure to match this range.
- Pull the sampler offline to inspect the tube/seal arrangement for excessive buildup of process material or damage to the sample tube. If there’s buildup or damage, replace the sample tube.
- Check to be sure the drive arm is connected correctly and not slipping.
|
| The sample tube stroke is too slow |
- Verify there is 60-100 PSI air pressure to the cylinder. If not, increase the air pressure to match this range.
- Check the solenoid valve and, if necessary, adjust the flow restrictor/exhausts.
- Check the packing nut. If it’s too tight, this could cause the sample tube hang up.
- Check to see if the sample tube is bent or deformed.
- Replace or repair the air cylinder.
- Ensure the sample tube is sustained and mounted properly.
|
| There is excess sample |
- Check to see if the sample tube is stuck in the process.
- Ensure the airlines aren’t crossed.
|
PR Automatic Samplers
The Sentry PR sampler's air cylinder moves a sample probe into the process stream. The free-flowing materials sampled is discharged through a flexible hose to a collection point. Material characteristics are not affected by the sampler because no moving parts convey the sample material to the sample container.
| Problem |
Solution |
| The sampler is leaking |
- Check the seals and spacers and replace them if they look worn.
- Check the sample tube.
- If the black QPQ coating or the brass colored NEDOX coating is worn through, the sample tube should also be replaced.
|
| The sampler tube won't extend or retract |
- Verify there is proper air pressure to the cylinder. If not, increase the air pressure.
- Pull the sampler offline to inspect the tube/seal arrangement for excessive buildup of process material or damage to the sample tube. If there’s buildup or damage, replace the sample tube.
- Verify the proper adjustment of the speed control valve.
|
SBC Controllers
The Sentry SBC controller is a dedicated logic control system that can control any automatic sampler in the Sentry product line.
| Problem |
Solution |
| The controller isn't operating |
- Check the pneumatic and/or electric power source to verify that the correct voltage and air pressure is bring supplied to the controller.
- Have a qualified technician run a complete operating check of timing circuits, remote contact inputs and/or flow counter inputs.
|
| The remote start function isn't working |
- When using the remote start function, you’ll need to supply an N/O contact. You must enable this feature in the options menu for it to operate properly.
|
| The remote enable function isn't working |
- When using the remote enable function, it’s necessary to remove the jumper between TB2-1 and TB2-2. If this jumper isn’t removed, you’ll still be able to actuate the sampler from the controller.
|
| The buttons won't respond when pressed |
If the controller was up and running and the plant observed a power outage or if the voltage supplied to the controller fluctuates, the controller automatically goes into “IDLE” mode. While in this mode, certain buttons are disabled.
To change the state of the controller from “IDLE” to “RUN”:
- From the main screen, press the keys together. This will take you to the “system” menu.
- Arrow down to “view status” and press enter.
- Once “mode” is highlighted, press enter again and change the status from “IDLE” to “RUN”.
- Exit this screen and press “main”.
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Automatic sampling helps you capture representative samples simply, safely and accurately. Contact us at +1-262-567-7256 or complete our online contact form to discuss how Sentry automatic sampling systems can help you achieve safe, simple and accurate sampling results.
