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5 - Programming Overview
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Power Fail Operation
The Agilent E4370A MCCD can operate in one of two power-fail shutdown modes. The mode is set by
the cfSetShutdownMode() command. When the mode is set to CF_AUTO, a true signal on the
CF_POWER_FAIL_IN digital input will cause the Agilent MCCD to perform a shutdown, at which time
it saves its state in nonvolatile memory. When the mode is set to CF_MANUAL, an automatic shutdown
is not performed (API commands such as cfShutdown must be used to do it manually). The
CF_POWER_FAIL_IN digital input signal is only acted on if cfShutdownMode = AUTO.
It takes the Agilent MCCD firmware about 20 milliseconds to recognize the state of the digital
CF_POWER_FAIL_IN signal. Additionally, a programmable delay set by the cfSetShutdownDelay()
command determines how long the CF_POWER_FAIL_IN signal must be true before an automatic
shutdown occurs. If the CF_POWER_FAIL_IN signal is true longer than the delay time set by
cfShutdownDelay, the Agilent MCCD will shut down. If the CF_POWER_FAIL signal goes false before
the expiration of the cfShutdownDelay time, no shut down occurs.
The purpose of this delay is so that the Agilent MCCD doesn't shut down every time the power fails for
more than 20 ms. For example, if the Agilent MCCD is connected to a UPS that can keep it running for 5
minutes, set cfShutdownDelay time for 4 minutes. This way, the power must be out for 4 minutes before
the Agilent MCCD shuts down. Since 4 minutes is less than the 5 minute UPS holdup time, there is no
danger that power loss will occur. If the power returns (as indicated by CF_POWER_FAIL_IN = false)
before the 4 minute delay expires, no shutdown occurs and the system has successfully handled a short ac
power loss.
Use the following functions to program and control a powerfail shutdown:
cfSetShutdownMode();
cfSetShutdownDelay();
cfSetServerTimeout();
cfSetAutoConnect();
cfShutdown();
The following functions also have capabilities that apply to a powerfail shutdown:
cfSetDigitalConfig();
cfGetInstStatus();
cfSaveOutputConfig
To restart the instrument by recalling a saved shutdown state use:
cfRestart();
Instrument State Storage
The instrument can store several instrument states. The entire state of the instrument, including the
defined sequence steps and tests, is stored in non-volatile memory under a user defined name.
Use the following functions to control instrument states:
cfStateSave();
cfStateRecall();
cfStateList();
cfStateDelete();
To reset the instrument to its power-on state:
cfReset();