Functional Overview

Table 2- 2: LED fault codes

 

ON/STBY

 

Main power

 

State

LED

Fault LED

relay

Description / suggested action

 

 

 

 

 

Standby

Off

Off

Off

No power. Press the ON/STBY switch for normal operation. Check

 

 

 

 

that the instrument power cord is plugged into the local power supply.

 

 

 

 

 

On

On

Off

On

Normal operation.

 

 

 

 

 

Cold

Flashing

Off

On

The LCD may be damaged if operated at low temperatures. If the

 

 

 

 

internal temperature sensors detect a low temperature, this fault code

 

 

 

 

will be asserted. Let the unit warm up and cycle the power or press

 

 

 

 

the ON/STBY switch for normal operation to occur.

 

 

 

 

 

Momentary

On

On

On

This is a transient state. It should never last more than one second. It

fault

 

 

 

occurs when the internal sensors detect that one of the internal

 

 

 

 

supplies is out of the allowable range. In this state, the instrument will

 

 

 

 

be reset.

 

 

 

 

This state can occur due to an intermittent problem that requires

 

 

 

 

service or from a drop-out on the AC line. If the fault persists for more

 

 

 

 

than one second, then the instrument will go to the Power Supply

 

 

 

 

Fault state.

 

 

 

 

It is normal for the momentary fault state to be asserted when the AC

 

 

 

 

line is removed while the instrument is running.

 

 

 

 

 

Power supply

Off

On

Off

If the internal monitors detect that one of the internal power supplies is

fault

 

 

 

out of its allowed range, the instrument will shut down and the Power

 

 

 

 

Fault LED code will be asserted. This can be triggered by multiple

 

 

 

 

drop-outs on the AC power supply to the instrument.

 

 

 

 

If this fault code is present, press the ON/STBY switch to reset the

 

 

 

 

instrument. If the fault code reoccurs, refer the instrument to qualified

 

 

 

 

service personnel. If the waveform monitor seems to be operating

 

 

 

 

properly, monitor the AC power supply to be sure there are no

 

 

 

 

problems in the power source.

 

 

 

 

 

Overtemp

Off

Flashing

Off

The internal temperature sensors will shut down the instrument at

fault

 

 

 

75 _C to prevent damage to the components if the ambient

 

 

 

 

temperature is too high or if the airflow is blocked.

 

 

 

 

If this occurs, the Overtemp fault code will be asserted. Let the

 

 

 

 

instrument cool down and cycle the power or press the ON/STBY

 

 

 

 

switch to resume normal operation.

 

 

 

 

 

EC self test

Flashing

Flashing

Off

This is asserted if the Environmental Controller is not able to test the

failed

 

 

 

temperature sensors and fan circuits. If this occurs, refer the

 

 

 

 

instrument to qualified service personnel.

 

 

 

 

 

WFM700 Series Waveform Monitors User Manual

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