User guide

901-10037001/1.1 FS 20/25 Operators Manual

Page 5.4 Maintenance and Troubleshootin

Kongsberg Simrad Mesotech Ltd.

Port Coquitlam, BC - Canada

5.2.2 Trawl Cable Requirements

For whatever cable type and length used, the following specifications must be met

for operation with the Simrad FS Trawl Monitoring system:

Cable Closed Loop Resistance: <100Ω

Signal Attenuation Through Cable: <40 dB (1/100 signal amplitude) @ 55 kHz

<20 dB (1/10 signal amplitude) @ 12 kHz

The cable closed loop resistance determines the maximum voltage drop along the

trawl cable. For proper operation, the trawl unit electronics require 55 - 140 Vdc @

1A maximum. For typical operation, the current is approximately 300mA with peaks

to 500mA.

Compensation for signal losses over the long trawl cable is done automatically within

the HP/PC processor unit each time it is powered up. In this way, changes to the

cable losses do not affect the intensity of the sonar return displayed.

5.3 HANDLING & MAINTENANCE

The most common causes of failures to the Simrad FS Trawl Monitoring system are:

• Trawl cable and/or winch slip ring problems.

• Sonar head and sensor module connector and interconnect cable failures, or

• Excessive impacts and/or physical damage to trawl unit electronics.

In all three of these cases, proper handling and maintenance can significantly

reduce the frequency of FS failures.

The following sections outline the recommended handling and maintenance for the

FS system.

5.3.1 Wheelhouse Electronics

Once installed, these units require little maintenance other than removing dust. A

damp, lint-free cloth should be used for this purpose. Note also that it is absolutely

essential that these units are receiving proper ventilation, particularly if the boat is

operating in warm climate locations.