User manual

Chapter 4 Configuration
Page 65 ©February 2009
Scaling is configured in the “Sensitivities” section of the configuration software. If you select a
new sensitivity/scaling block, you can select/deselect sensitivity or scaling or both. There is no
relationship between sensitivity and scaling - we use the same configuration area as it is
convenient because both features use blocks of I/O registers.
In the first example, a block of I/O registers is
configured for both sensitivity and scaling. I/O
block 0 to 79 (total of 80 registers) is configured
with a sensitivity value of 500. The same block
has scaling configured converting the range
16384-49152 on the radio side to 0-4095 on the
data bus side.
This is an example of converting a “4-20mA
value” to a “12-bit value”. Note that the scaling
works in both directions - for values being read
from the I/O registers to the data bus, and values
written from the data bus to the I/O registers.
Any values outside of the scaling range are set to
the minimum or maximum value. For example,
if the data bus read a value of 10,000 from a
register in this block, as it is less than the
minimum range on the radio side (the min. is
16,384) it will be transferred as 0 which is the
minimum value on the data bus side. If a value
of 65,535 is read from another register, then as it is more than the maximum value on the radio
side (max. value is 49,152), then the value is transferred as 4095 which is the maximum on the
data bus side. This works in both directions - if the data bus tries to write a value of 10,000 to an
I/O register in this block, it will be written as value 49,152 (which is the max. value on the radio
side.
Data-bus
Value
4095
0
0 16384 49152 65535
Radio I/O Reg. Value
Radio
I/O Reg.
Value
49152
16384
0
0 4095
Data-bus Value
Transferring values from
Radio I/O Reg. to Data Bus
Transferring values from
Data Bus to Radio I/O Reg.