Rockwell Automation 61C544A RTD Module - Manual (Page 26)

4Ć10
4.1.15 Configuration Command Register (Register 31)
Register 31 defines what action should be taken if an input value is
out of range, what temperature units should be used, what type of
RTD is used, and the average AĆC line frequency. The register also
contains the Configure Command Code. See figure 4.10.
Bits 1 and 0 = When An Input Value Is Out of Range
0ă0ă=ăRetain Old Input Value
0ă1ă=ăForce Input Value to Low Low Alarm Value
1ă0ă=ăForce Input Value to High High Alarm Value
1ă1ă=ăRetain Old Input Value
Bit 2 = Temperature Unit
0 = Celsius
1 = Fahrenheit
Bit 3 = RTD Thermal Response
0 = European Curve: Alpha = 0.00385
1 = American Curve: Alpha = 0.00392
Bits 5 to 4 = Reserved for Future Use
Bit 6 = Cycle Frequency Averaging
0 = Enable
1 = Disable
Bits 11 to 7 = Reserved for Future Use
Bits 15 to 12 = Configure Command Code
0 0 0 0 = READY State
0 0 0 1 = Reset Configuration For This Channel
0 0 1 0 = Read Configuration For This Channel
0 0 1 1 = Write Configuration For This Channel
0 1 0 0 = 50 Hz AĆC Line Frequency
0 1 0 1 = 60 Hz AĆC Line Frequency
Register 31
Bits 0Ć15
RW RW RW RW - - - - - RW RW RW RW RW
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
- -
Figure 4.10 Ć Configuration Command Register
When configuring a channel, you must define values for registers 23
through 30 before writing a value to register 31. Register 31 must be
the last register that you write to as you configure each channel.
When you are finished with register 31 for the channel you are
configuring, and the module has processed the information, the
module will set bit 15 of register 22 equal to one. You must then set
bits 12 to 15 of register 31 equal to zero. This places the module in
the READY state. The module then resets bit 15 of register 22 which
indicates that it is ready to configure another channel via register 31.
If you attempt to enter another command before resetting bits 12 to
15 of register 31, a configuration error will result.
Bits 0 and 1 specify what action should occur when an input value is
out of range. The default condition is to retain the old input value
from the data registers (0 to 15).