Guildline 6634A Resistance Standard, Руководство оператора

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Section 1
OM6634A-B-02
4 January 2019 1-3
Figure 1-2: Rear View
1.4. REAR PANEL CONNECTORS AND CONTROLS
The rear panel connectors and controls are illustrated in Figure 1-2. They include power entry,
resistor terminals and guard/ground terminals. The terminals are not installed for resistance
element values that are not provided in specific models.
1.4.1. Line Input Connector
The Line input connector is a combination standard male 3-prong AC connector, power
ON/OFF switch and fused line input voltage selector. The line input voltage selector
consists of a four-position selector and a fuse holder. The selector allows switching for
100 VAC, 120 VAC, 220 VAC and 240 VAC. A ½ amp time delay fuse is provided for
100/120 VAC operation and a ¼ amp time delay fuse is provided for 220/240 VAC
operation.
1.4.2. Resistor Terminals
There are a set of four terminal input/outputs for each installed resistance element. Each set
consists of four low thermal binding posts labelled with the nominal value of each of the
standard resistors. Each 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 specific
standard resistor. 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.
1.4.3. Guard Terminal
The GUARD terminal consists of a four-way white binding post. The GUARD terminal is
connected to the isothermal chamber which contains the standard resistors. This chamber is
isolated from chassis ground and may be guarded through the guard terminal separately
from the power ground.