User Manual
Appendix B
GFK-1742F
Jan 2020
DSM314 Communications Request Instructions
410
%R00207
–
Number of Parameters to send = 16
%R00208 - %R00239
–
Parameter data to be sent
Figure 188
Logic for Parameter Data (not Shown)
Additional logic will be required to load your data into registers %R00208 - %R00239 so that
it can be sent to the DSM314 parameters. (The value in double word %R00208/%R00209
will be sent to Parameter 1, the value in %R00210/%R00211 will be sent to Parameter 2, and
so on, until finally, the value in %R00238/%R00239 will be sent to Parameter 16.) The
method to be used for loading the data into these registers depends upon your application.
If the data values will not change, constants can be moved into the registers using Block
Move and/or Move instructions. If the values are to change, they could be moved into the
registers from an operator interface device.
Handling Double Integer Parameter Values and Input Value Scaling
The data in the single precision registers (16 bits) needs to be converted to double-integer
(32 bits) form because the DSM’s parameters are double
-integer size. A convenient way to
do this is to use a Double Integer Multiply (MUL DINT) instruction to move input data into
the registers whose contents will be sent to the DSM. There are two possible advantages to
this approach:
•
This is an easy way to convert single integer registers to double-integer form.
•
It lets you easily scale the input values if you should need to. The term scaling refers
to multiplying and/or dividing a value to create a new value that is proportional to
the original value. For example, multiplying an input value by two, then dividing it
by 3 would result in an output value that is always 2/3 the size of the input value.
Scaling is often required in a servo system to match the actual distance moved to
the distance commanded. It is doing so, it provides
the function of an “electronic