Analog Outputs - GE 469 Instruction Manual

469
Electrical Installation
Motor Management Relay
FIGURE 3–21: Loop Powered Transducer Connection

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 3–12: Typical Wiring Diagram on page 3–9, 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 =
load
V / I . For 0 to 1 mA, for example, if 5 V full scale is required to
full scale max
correspond to 1 mA, R = 5 V / 0.001 A = 5000 Ω. For 4 to 20 mA, this resistor
load
would be R = 5 V / 0.020 A = 250 Ω.
load
RTD Sensor
a) Description
Connections
The 469 monitors up to 12 RTD inputs for Stator, Bearing, Ambient, or Other
temperature monitoring. The type of each RTD is field programmable as 100 Ω
Platinum (DIN 43760), 100 Ω Nickel, 120 Ω Nickel, or 10 Ω Copper. RTDs must be
three wire type. Every two RTDs shares a common return.
The RTD circuitry compensates for lead resistance, provided that each of the three
leads is the same length. Lead resistance should not exceed 25 Ω per lead for
platinum/nickel RTDs or 3 Ω per lead for copper RTDs. Shielded cable should be
used to prevent noise pickup in the industrial environment. RTD cables should be
kept close to grounded metal casings and away from areas of high electromagnetic
or radio interference. RTD leads should not be run adjacent to or in the same
conduit as high current carrying wires.
GE Multilin
3–17
http://www.GEindustrial.com/multilin