Rockwell Automation 61C544A RTD Module - Manual (Page 27)

4Ć11
Bit 2 specifies whether the input values are in degrees Fahrenheit or
in degrees Centigrade. The default is degrees Centigrade.
Bit 3 defines the RTD Thermal Response Curve. A value of zero
indicates a European curve. A value of one indicates an American
curve. The default is a European curve.
Bits 4 to 5 are reserved for future use.
Bit 6 defines whether or not cycle averaging is enabled for the
channel specified in register 23. The default condition (0) enables
cycle averaging.
Bits 7 to 11 are reserved for future use.
Bits 12 to 15, when equal to 0, enable the READYstate, which is the
default condition. When the module is in the READYstate, it is ready
to receive a configuration command.
When bits 12 to 15 are set to a binary 1, 2, or 3, their operations refer
to the channel specified in register 23:
D A binary 1 (RESET) resets the channel's configuration by clearing
its data register (registers 0Ć15) and resetting its bit in the status
registers (registers 16Ć21).
D A binary 2 (READ) locates the channel's current configuration
information in memory and loads it into registers 26 to 30.
D A binary 3 (WRITE) transfers the channel's configuration
information (registers 26 to 30) into the module's memory,
configures the channel, and then sets its bit in the status registers
(registers 16Ć21).
When bits 12 to 15 are set to a binary 4 or 5, they reflect the AĆC
power line frequency. The default is 60 Hz.
4.2 RTD Configuration Procedure
RTD configuration information is stored onĆboard the RTD module. At
system powerĆup, default values are automatically placed in the
module's memory. You can change these default values on a
channelĆbyĆchannel basis. See figure 4.11.
To do this, you need to set bits 12 to 15 of register 31 equal to zero to
make sure the RTD module is in the READYstate and then place a
value in register 23 and registers 26 through 30 for each RTD
channel you wish to configure:
D Channel Number Register (Register 23)
D Number of Samples Register (Register 26)
D High High Alarm Register (Register 27)
D High Alarm Register (Register 28)
D Low Alarm Register (Register 29)
D Low Low Alarm Register (Register 30)
D Configure Command Register (Register 31)