Guildline 6634A Resistance Standard, Руководство оператора

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Section 1
OM6634A-B-02
4 January 2019 1-2
Note that if 0.001 and/or 0.01 values are ordered they physically take more space so are
delivered with fewer elements.
Figure 1-1: Front View
1.3. FRONT PANEL INDICATORS AND CONTROLS
The front panel indicators and controls are illustrated in Figure 1-1. They are provided to
indicate power status, heater operation and temperature status.
1.3.1. Power
The POWER indicator is lit when the AC power is applied to the unit and the power
ON/OFF switch on the rear panel is “ON”.
1.3.2. Heater
The HEATER indicator is lit when power is being applied to the heater.
1.3.3. Over Temperature
The OVER TEMP indicator is lit when the internal temperature has exceeded 34 °C

3

C. This may occur when the unit is operated in an ambient temperature in excess of the
operating temperature, or in the event of control failure.
1.3.4. PRT
The platinum resistance thermometer, imbedded within the temperature controlled
chamber, is configured as a four terminal resistor. The four terminals terminate in four
low thermal binding posts labelled “PRT”. The set of terminals consists of two black
binding posts for the 'P1' and ‘C1’ terminals, and two red binding posts for the ‘P2’ and 'C2'
terminals of the PRT. The ‘C’ terminals are to be connected to the current source and the
‘P’ terminals are to be connected to the potential measuring circuit of the resistance
measuring device. The temperature sensitivity of the PRT is 0.392

/

C. The resistance
at 30

C is provided in the Report of Calibration. For accurate temperature measurement,
the resistance must be measured in four wire mode with an excitation current of 1 mA or
less.