Functional Overview
Table 2- 2: LED fault codes
| ON/STBY |
| Main power |
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State | LED | Fault LED | relay | Description / suggested action |
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Standby | Off | Off | Off | No power. Press the ON/STBY switch for normal operation. Check |
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| that the instrument power cord is plugged into the local power supply. |
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On | On | Off | On | Normal operation. |
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Cold | Flashing | Off | On | The LCD may be damaged if operated at low temperatures. If the |
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| internal temperature sensors detect a low temperature, this fault code |
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| will be asserted. Let the unit warm up and cycle the power or press |
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| the ON/STBY switch for normal operation to occur. |
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Momentary | On | On | On | This is a transient state. It should never last more than one second. It |
fault |
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| occurs when the internal sensors detect that one of the internal |
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| supplies is out of the allowable range. In this state, the instrument will |
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| be reset. |
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| This state can occur due to an intermittent problem that requires |
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| service or from a |
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| than one second, then the instrument will go to the Power Supply |
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| Fault state. |
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| It is normal for the momentary fault state to be asserted when the AC |
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| line is removed while the instrument is running. |
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Power supply | Off | On | Off | If the internal monitors detect that one of the internal power supplies is |
fault |
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| out of its allowed range, the instrument will shut down and the Power |
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| Fault LED code will be asserted. This can be triggered by multiple |
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| |
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| If this fault code is present, press the ON/STBY switch to reset the |
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| instrument. If the fault code reoccurs, refer the instrument to qualified |
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| service personnel. If the waveform monitor seems to be operating |
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| properly, monitor the AC power supply to be sure there are no |
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| problems in the power source. |
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Overtemp | Off | Flashing | Off | The internal temperature sensors will shut down the instrument at |
fault |
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| 75 _C to prevent damage to the components if the ambient |
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| temperature is too high or if the airflow is blocked. |
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| If this occurs, the Overtemp fault code will be asserted. Let the |
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| instrument cool down and cycle the power or press the ON/STBY |
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| switch to resume normal operation. |
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EC self test | Flashing | Flashing | Off | This is asserted if the Environmental Controller is not able to test the |
failed |
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| temperature sensors and fan circuits. If this occurs, refer the |
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| instrument to qualified service personnel. |
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WFM700 Series Waveform Monitors User Manual | 2- 3 |