Signal Wiring Recommendations; Testing The System - Teledyne 2010A Operating Instructions Manual

Thermal conductivity analyzer

Table of Contents

Thermal Conductivity Analyzer

2-11 Signal Wiring Recommendations

The signal leads are the bias and sensor leads ref fig. 3.4, and reference

D-70731 interconnection diagram. The maximum interconnection distances

between the 2010 control unit and the analysis unit is limited by the sensor

signal requirements. The sensor has two limiting factors. The first is series

resistance which is limited to a maximum of 2.5 ohms. Refer to the intercon-

nection diagram for wire gages and distances which will meet this require-

ment.

The second issue is one of signal quality. At greater distances prob-

lems associated with signal degradation increases. Signal degradation prob-

lems have two major issues. The first is associated with the local installation

environment. The number, proximity, and power associated with local

sources of EMI radiation can not be accounted for by TAI. These issues can

only be controlled by the end user. The other factor is the amplitude of the

signals generated by the thermal conductivity cell. This signal level is a

function of the gas composition of the gases involved. This signal level can

vary from micro-volts to mili-volts dependent on application. Consult TAI

for recommendations based on sample stream composition. Signal quality

and operating distances can be increased by the uses of better quality

shielded low loss cable. The cable configuration should be twisted pair with

double shielding for best performance. The signal cable should not be run

with AC power or digital signals.

After The Control Unit and the Analysis Unit are both installed and

interconnected, and the system gas and electrical connections are complete,

Figure 3-6: FET Series Resistance

Teledyne Analytical Instruments

Part II: Analysis Unit

Part II: 2-7

Table of Contents

Table of Contents