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2.2 ELECTRICAL
2 INSTALLATION
2.2.9 ANALOG INPUTS
The 469 provides terminals for four 0 to 1mA, 0 to 20mA, or 4 to 20mA current input signals (field programma-
ble). This current signal can be used to monitor external quantities such as vibration, pressure, or flow. The
four inputs share one common return. Polarity of these inputs must be observed for proper operation The ana-
log input circuitry is isolated as a group with the analog output circuitry and the RTD circuitry. Only one ground
reference should be used for the three circuits. Transorbs limit this isolation to ±36 V with respect to the 469
2
safety ground.
In addition, the +24 V DC analog input supply is brought out for control power of loop powered transducers.
Refer to Section 1.2: SPECIFICATIONS on page 1–5 for maximum current draw from this supply.
Figure 2–17: LOOP POWERED TRANSDUCER CONNECTION
2.2.10 ANALOG OUTPUTS
The 469 provides 4 analog output channels which may be ordered to provide a full-scale range of either 0 to
1 mA (into a maximum 10 kΩ impedance) or 4 to 20 mA (into a maximum 1200 Ω impedance). Each channel
can be configured to provide full-scale output sensitivity for any range of any measured parameter.
As shown in Figure 2–10: TYPICAL WIRING DIAGRAM on page 2–8, these outputs share one common
return. Polarity of these outputs must be observed for proper operation. Shielded cable should be used, with
only one end of the shield grounded, to minimize noise effects.
The analog output circuitry is isolated as a group with the Analog Input circuitry and the RTD circuitry. Only one
ground reference should be used for the three circuits. Transorbs limit this isolation to ±36 V with respect to the
469 safety ground.
If a voltage output is required, a burden resistor must be connected at the input of the SCADA measuring
device. Ignoring the input impedance of the input, R
= V
/ I
. For 0 to 1 mA, for example, if 5 V full
load
full scale
max
= 5 V / 0.001 A = 5000 Ω. For 4 to 20 mA, this resistor would be
scale is required to correspond to 1 mA, R
load
= 5 V / 0.020 A = 250 Ω.
R
load
2-14
469 Motor Management Relay
GE Power Management
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