Rtd Temperature - GE 869 Instruction Manual

MONITORING

RTD Temperature

NOTE:
NOTE:
NOTE:
4–324
RTD Wiring Diagram
Figure 4-136: RTD Wiring diagram
To enhance the accuracy of the RTD, ensure all 3 cables are of the same length and gauge.
In addition, the Compensation and Return wires must be connected on the RTD side and
not on the relay side.
RTD Inputs
Hardware and software is provided to receive signals from external Resistance
Temperature Detectors (RTDs) and convert these signals into a digital format for use as
required. These channels are intended to be connected to any of the RTD types in common
use.
Depending on the order code, the 869 can be furnished with up to two optional RTD cards.
Each card has six RTD input channels. Only slots "B" and "C" can accept RTD cards. When
two RTD cards are used, then inputs on the card inserted into slot "B" are labelled 1 to 6
and inputs on the card inserted into slot "C" are labelled 7 to 12.
If only one RTD card is ordered at the time the relay is ordered, this RTD card is always
shown in slot B. The order code selection does not allow for an RTD card in slot C, if no RTD
card is ordered in slot B.
An LVIO card ordered in Slot G will contain an additional RTD input on the card. It will be the
highest RTD number shown (i.e. if 1 additional RTD card is used, then the LVIO RTD will be
RTD #7).
An alphanumeric name is assigned to each channel; this name is included in the channel
actual values. It is also used to reference the channel as the input parameter to features
designed to measure this type of parameter. Selecting the type of RTD connected to the
channel configures the channel. The conversion chart is shown in the RTD Temperature vs.
Resistance table.
Table 4-36: RTD Temperature vs. Resistance
TEMPERATURE
°C °F
–40 –40
–30 –22
–20 –4
RESISTANCE (IN OHMS)
100 Ω PT 120 Ω NI
(IEC 60751)
84.27 92.76
88.22 99.41
92.16 106.15
869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS
100 Ω NI 10 Ω CU
77.30 7.49
82.84 7.88
88.45 8.26