| Installation, Operation & Maintenance Manual |
MSL600 | IP262/Z0, Rev. AB |
February 2012 | |
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The transducer may take up to 1 hour to reach thermal equilibrium. Therefore, it may take some time to restore accurate blanket level readings. When the arm tilts out of the supernatant the MSL600 holds the last supernatant temperature reading from the transducer. When the transducer falls back into the supernatant the MSL600 starts to make measurements again.
When the MSL600 measures the supernatant temperature at the transducer, as long as the temperature is within the programmed normal limits for a supernatant then the system uses this measured temperature for speed of sound compensation.
If the measured temperature is outside of these limits then the MSL600 uses the last held temperature reading. This state will continue until a valid temperature reading is again obtained from the transducer in the supernatant.
The upper and lower temperature points are programmable as HMI Engineering parameters. The default values are
Because the tilt switch is sensitive to vibration as well as angle it is
5.9 Digital input
Parameter P340 is used to assign the status of the digital input to an alarm relay if desired. This allows the user to stop measurement whilst the blanket is known to be disturbed and meaningful results would not be obtained. E.g. during high
When the digital input is active all measurements continue as normal and the LED still flashes. The sonar pulse echo display continues to update with live data. However, the blanket level is held at its last value. The trend graph continues to update, relays and current output remain active, and logging continues using the held blanket level.
Digital input active means either a short across the terminals, i.e. from a contact closure or a PLC driving low, i.e. going to ‘0’.
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