The Trek Model 541A Electrostatic Voltmeter (pictured with the Model 541PR-S probe) provides accurate non-contacting measurements of the electrostatic surface voltage associated with EOS/ESD processes. The instrument is configured with a miniature electrostatic field chopper probe that can be remotely located and easily positioned within process equipment to provide highly accurate, non-contacting, DC-stable, spacing-independent voltage measurements in either ionized or non-ionized environments. A 20x4 alphanumeric LCD screen displays the present measured voltage, the positive peak voltage, the negative peak voltage and additional menu information.

• Measurement Range 

    Model 541A-1: ±1 kV DC or peak AC 

    Model 541A-2: ±100 V DC or peak AC 

• Measurement Accuracy: Better than ±1% of full scale over a probe-to-surface separation of 2.5 mm ± 1mm 

• Alphanumeric LCD Display: 20 x 4 characters

Alarms	Activated if measured voltage exceeds preset threshold limits; positive/negative limits may be programmed separately
Visual	Front-panel LEDs illuminate when thresholds are reached
Audible	ON/OFF programmable pulsating or continuous tone. (+) and (-) alarms have different tone rates for the pulsating tone selection
Alarm Relay Output	Form C relay contact with barrier strip terminals; changes state when voltage thresholds are met or exceeded
Alarm Digital Output	TTL output with a TTL low (0 to 0.8 V) as the alarm “ON” status; TTL high (2.5 to 5.0 V) indicates a normal condition
Reset Button	Resets alarms and peak hold to zero
Zero Control	Adjustable to produce zero volts when probe coupled to a known zero voltage source
Alphanumeric LCD Displa	20 character by four line (20x4) LCD displays the present voltage and holds the most positive and most negative values
Ground Receptacle	Banana jack
Serial Port and USB Port	Provides control of specific functions and acquires sensor data utilizing Trek software and a PC connected to the RS-232 serial port or the USB Type B port (connectors are on back panel)
Current Output	Provides a current of 4 mA to 20 mA representing -1 kV to +1 kV (541A-1) and -100 V to +100 V (541A-2)