YOKOGAWA EML500 Series, Руководство пользователя, Страница: 19 / 85

2-6
IM80B80T10E 21th Edition : Jul.1,2007-00
< 2.OVERVIEW >
(8) Input Signal: 1 circuit (for back up by GPS)
 Digital signal
Input circuit: Isolated by photocoupler
510Ω
P
N
2SK117
1S955
TLP553
(9) Ambient Conditions
Temperature: -15°C to +55 °C (when operating)
-20 °C to +60 °C (when not operating)
Humidity : up to 95 % RH (no condensation)
Vibration : 5 Hz to 12.5 Hz ..... ±1.6 mm
12.5 Hz to 25 Hz ..... ± 0.38 mm
25 Hz to 50 Hz ..... ± 0.1 mm
Waterproofing : IP 22
Junction box ..... IP 55
Sensor unit ..... 0.5 MPa for submerged section and IP 55 for the upper section
Power line noise : There must be no noise when a pulse of 100 / 400 nsec and 1500 V is applied for three
minutes.
Insulation resistance : at least 10MΩ, using a 500 V megger (excluding the sensor and electronic circuits)
Withstanding voltage : 1500 V AC, for 1 minute (excluding the sensor and electronic circuits)
2.4 Handling Precautions
(1) If there are contaminants or microorganisms adhering to bottom of the ship or the tip of the
measurement rod (electrodes), the indicated speed may be lower than the actual speed. The
bottom of the ship should always be kept clean. For cleaning and inspection, refer to Section
5.2 in Chapter 5.
(2) When closing the seawater valve, first pull up the measurement rod as far as the attached
chain allows.
(3) If the ship is at anchor, pull the measurement rod all the way up and close the seawater
valve.
(4) If the ship will remain in port for a log time, remove the chain and keep the measurement rod
on board.
(5) The “FWD” marking on the measurement rod must face in the direction of the bow.
Otherwise, the detected speeds will be lower than the actual ones.
(6) The tip of the measurement rod is fragile. Handle it very carefully.
(7) Even when the ship is at anchor, a slight speed may be indicated if the water is flowing past.