Temperature Compensation; Communication Noise Rejection - ABB Platinum standard Series Product Instruction

DESCRIPTION AND OPERATION

Temperature Compensation

FUNCTIONAL OPERATION
2 - 6
The FSK communication technique makes it possible to com-
municate in the presence of electrical noise. Figure
how the ability to communicate varies with the amplitude and
frequency of the noise. This graph represents a typical instal-
lation and applies only when one noise frequency is present.
The graph indicates that the FSK communication technique
tolerates up to two volts of noise amplitude at 60 hertz. This
tolerance decreases as the noise frequency approaches the
FSK communication
30.5 kilohertz.
4
3
N O IS E A M P L IT U D E
(VO LT S )
2
1
0
1
Figure 2-6. Communication Noise Rejection
The transmitter electronics monitor the temperature of the cell
assembly. This is accomplished by monitoring the resistance
of the coils within the cell. This technique provides a true cell
temperature measurement and the transmitter uses it to cal-
culate an advanced correction for the cell output based on the
programmed cell temperature characteristics. The transmitter
also compensates the four to 20-milliampere output for tem-
perature changes within the electronics housing. Type PTSD
pressure transmitters monitor and compensate for the
dynamic temperature difference between the high and low
sides of the cell. The cell temperature can be monitored on the
Type STT terminal.
frequencies of 19.0 kilohertz
6 0 H Z
1 0 1 0 0 1 ,00 0
N O IS E F R E Q U E N C Y (H Z )
2-6 shows
and
1 9 .0 kH Z
1 0 ,0 0 0
WBPEEUI110504A0