KONGSBERG PI50 Fishing Troubleshooting Guide

KONGSBERG PI50 System Troubleshooting Guide

Simrad PI50 is a wireless fishing monitoring system designed specifically for commercial fisheries, widely used in bottom trawl, mid trawl, purse seine, and Danish style trawl operations. It receives various sensors installed on the net (depth, height, net mouth expansion, catch, bottom contact, temperature, geometric posture, etc.) through underwater acoustic communication, providing real-time net status and marine environment data for the crew. Quick and accurate troubleshooting is key to ensuring fishing efficiency when the system experiences signal loss, data jumps, or abnormal readings. This article is based on the official PI50 operation manual, extracting a complete guide from sensor configuration, receiver calibration to typical fault handling, to help on-site engineers and onboard operators systematically diagnose and solve common problems in the PI50 system.

System composition and communication principles

The PI50 system consists of the following core units:

Processor unit (computer): runs PI50 software, displays sensor data, and provides a user interface.

Sensor Receiver: Available in 6-channel (PI50) or 10 channel (PI60) models, responsible for receiving and decoding acoustic signals from underwater sensors.

Hydrophone: Installed at the bottom of the ship, it is divided into net type (beam horizontal 90 ° x vertical 30 °) and trawl type (50 ° x 30 °), and can also be used as an omnidirectional portable hydrophone.

Wireless sensors: including PI series and PX MultiSensor, can measure depth, height, net mouth expansion, catch, bottom contact, temperature, roll/pitch, net geometry, etc.

The sensor sends data to the hydrophone through acoustic pulses, and after demodulation by the receiver, it is transmitted to the computer through an RS-232 serial port (4800 baud, 8 data bits, no verification). Each sensor occupies one communication channel, while dual measurement sensors (such as expansion/depth) occupy two channels. The system supports a maximum of 6 or 10 measurement channels.

Understanding this communication link is the foundation of troubleshooting: any abnormality in any link (sensor battery, hydrophone installation, receiver power supply, serial cable, software configuration) may result in data loss.

Sensor configuration and common configuration errors

2.1 Sensor selection and parameter matching

In the Setup → Select Sensors dialog box, the operator needs to complete the following key configurations:

Select the sensor type (such as Depth 300m, Catch, Spread, etc.) from the Available Sensors list and click on it[ ▶] Add to the Selected Sensors list.

In the Selected Sensors list, adjust the upper and lower order of sensors to correspond to the screen display order.

The Sensor Configuration area needs to be set one by one:

Label ID: Sensor physical label number (must be unique).

Label Name: An alias used only for dialog box recognition.

Update Rate: It must be consistent with the update rate set internally by the sensor (Normal or Fast). The PX MultiSensor is fixed to Normal.

Sensor Value Name: The name displayed in the sensor view, such as "Left Mesh Panel" or "Right Mesh Panel".

Channel Number: The communication channel number (1-6 or 1-10) used by the sensor. When multiple sensors of the same type are used simultaneously, the channel numbers must be different.

Offset: The depth sensor is automatically filled in after calibration; Expanding the sensor requires manually inputting the offset of the connection point (± 99 m).

The most common configuration error:

Update Rate mismatch → No data or data refresh exception.

Duplicate Channel Number → Data Conflict, both sensors are invalid.

The depth sensor has selected the wrong range (such as selecting Depth 1000m when the sensor is a 600m version) → serious deviation in depth reading.

2.2 Special settings for dual measurement sensors

For dual channel sensors such as Spread/Depth and Height/Depth, two channels need to be occupied. When configuring:

Select "Spread/Depth" or "Twin Spread" in the Available Sensors instead of adding Spread and Depth separately.

The two Sensor Value Names of the dual measurement sensor can be named separately (such as "Left Mesh Depth" and "Left Mesh Expansion").

For Geometry measurement (requiring three sensors): one Geometry sensor (or PX MultiSensor) is placed in the center of the back mesh, and two remote sensors (or Mini-R responders) are placed on the mesh board. When measuring geometry, the PX MultiSensor on the mesh board must be installed "in reverse" (with the sensor tip pointing towards the back mesh).

Receiver settings and signal quality optimization

The receiver parameters directly affect the data stability and operating distance, which can be adjusted in the Setup → Receiver dialog box.

3.1 Detection Threshold

This parameter determines the sensitivity of the receiver to the signal. PI50 uses two ranges:

3-14: Increasing the value=raising the threshold, set to around 8 for extremely long distances (>1500 m) and low interference hours.

15-20: The main range for normal use, increasing the value=decreasing the threshold. The default value is 17.

Troubleshooting guidance:

When there is no sensor entering the water, random false data appears → the threshold is too low (the value is too large), and the value should be reduced (such as from 17 to 15) until the false data disappears.

Sometimes there is no data after the sensor is submerged → the threshold is too high (the value is too small), and the value should be increased (such as from 17 to 19).

Longest distance requirement (>1500 m): Try setting it to 8. If there is still interference, gradually increase until the interference disappears.

3.2 Filter Settings

Sensor Filter: Average multi frame data. Off (real-time), Weak (4 frames), Medium (8 frames), Strong (16 frames). When the operating distance is far but the data changes slowly, Wear can be used.

Catch/Bottom Filter: Suppresses fishing/bottom contact state jitter. Weak requires 2 stable transmissions before updating, while Strong requires 8 transmissions.

Multipath Filter: Suppresses reflections, spikes, and latency interference. Default On. Keep on in shallow water and multi reflection environments.

Phenomenon and Countermeasures:

The data jumps significantly but the trend is correct → Enable Multipath Filter.

Frequent flashing of catch indicator → Increase Catch/Bottom Filter intensity.

Large fluctuations in depth/expansion values without interference sources → Increase the Detection Threshold appropriately or enable the Weak Sensor Filter.

3.3 Identification of Interference Sources

Common interference comes from other acoustic equipment on board (echo sounder, sonar, Doppler log) or similar systems on nearby ships. Identification method:

Turn off the PI50 receiver and observe if the operating frequencies of other acoustic devices are similar (the PI50 operating frequency range is approximately 50-110 kHz).

Turn off other acoustic equipment on board one by one and determine the source of interference.

If it cannot be closed, you can try changing the Detection Threshold or using Multipath Filter.

Depth sensor calibration

The depth sensor must be immersed in saltwater for calibration to obtain accurate depth offset. Standard calibration process:

Attach a rope to the top suspension ring of the sensor and mark it 1 meter upwards from the bottom of the sensor.

Place the sensor in the water so that the mark is exactly level with the water surface (if you want to use the depth of the keel or transducer as a reference, adjust the mark accordingly).

In PI50, go to Setup → Calibration and click on Start Calibration.

The system automatically calculates the offset value and applies it. After completion, the sensor display should be 1.0 meter (or the selected reference depth).

Common reasons for calibration failure:

The sensor is not completely submerged or is not saltwater (with different densities of freshwater).

The water surface fluctuates greatly and the marking position is inaccurate → It is carried out in the still water area on the side of the ship.

The sensor battery is low → Replace the battery and recalibrate.

The depth reading is clearly incorrect but the calibration is normal: it is possible to select the wrong depth range (such as selecting 600m in the software when the actual sensor is 300m). Re select the correct version for Depth in Select Sensors.

Typical fault phenomena and troubleshooting

5.1 No sensor data, Pulse light does not flash

Receiver power supply: The receiver does not have a power switch, and if not in use for a long time, the power adapter needs to be disconnected. Check if the power adapter is functioning properly (24V DC output).

Serial communication: Confirm that the RS-232 cable connection between the computer and the receiver is correct (Rx → Tx, Tx → Rx, GND → GND), with a length not exceeding 50 meters. Check the COM port settings (4800,8, N, 1) in Setup → Installation → I/O Setup.

Hydrophone: Measure whether the hydrophone cable is broken; If there are two hydrophones (trawl/purse string), check if the selector is in the correct position.

Software license: If the license is invalid, communication is blocked. Check the Hardware ID and license status in Setup → Installation → Software License.

5.2 Some sensors have no data

Channel number conflict: Multiple sensors on the same channel → Use PI Configurator or PX Configurator software to change the channel number of one of the sensors and synchronously modify the Channel Number in Select Sensors.

Update rate mismatch: The sensor is set to Fast, select Normal in the software and change to the correct rate.

Sensor battery depleted: Test after charging. The PX sensor battery requires a dedicated charger.

Damage or water ingress: Check the shell and sealing ring.

5.3 Data jumps, spikes, or incorrect readings

Shallow water reflection: Enable Multipath Filter.

Strong interference: Gradually increase the Detection Threshold until the data is stable.

Bottom contact/fishing sensor false trigger: Increase Catch/Bottom Filter strength.

Error in offset value of extended sensor: Check if the Remote sensor is working properly on another mesh board and confirm the offset value (such as the distance from the installation point of the mesh board). You can temporarily set Offset to 0 for testing.

5.4 Geometry data anomalies

Check the relative position of the back mesh sensor and two remote sensors. Remote sensors must be installed in reverse.

Confirm that all three sensors are online and there are no conflicts in the channels.

When using PI Mini-R substitute, confirm that the responder is activated.

5.5 Invalid sensitivity adjustment of receiver

Restore default Detection Threshold=17, turn off all filtering, and manually trigger sensor (such as immersion activation) testing near the hydrophone. If there is no stable data, it may be due to misalignment of the hydrophone beam or sensor distance exceeding the range. In trawl operations, hydrophones should be installed at a location at the bottom of the ship that is not affected by flow noise interference.

Daily maintenance and preventive measures

Sensor maintenance: Rinse with fresh water after each use and check if the sealing ring is damaged. Ensure that the contacts are dry before charging.

Hydrophone inspection: Regularly clean the surface of the hydrophone to avoid the attachment of marine organisms. Check if the cable sheath is damaged.

Computers and receivers: Keep well ventilated and dry. Regularly check the serial port cable connection, re plug and unplug to ensure no oxidation.

Software and settings backup: Use Main → User Settings to save the complete configuration of different jobs (trawl, purse seine). Regularly export log files from C: ProgramData Simrad PI50 Log for technical support analysis.

Firmware upgrade: Contact the dealer to obtain the latest version and update the receiver firmware through the SysLoad program.

Emergency recovery

If the PI50 software crashes or does not respond:

Restart according to the correct procedure: First, close the PI50 application (click Exit in the top right corner of the Title Bar), then turn off the computer and wait for 10 seconds before restarting. It is strictly prohibited to directly cut off the power to avoid damaging the serial port parameters.

If the system prompts "No license" or Hardware ID changes, it may be due to a replacement of computer hardware, and you need to contact the dealer to reapply for a license.

If the indicator light inside the sensor receiver is abnormal (refer to the definition of the LED on the front panel of the receiver), it may need to be repaired.