User Manual Appendix B
GFK-1742F Jan 2020
DSM314 Communications Request Instructions 411
gearbox.” It can be used to allow for gear ratio, ballscrew pitch, encoder resolution,
and customer input value preference.
In the example below, the integer value from an Operator Input device (a 4-digit BCD
thumbwheel switch) will be multiplied by a factor of 1000, then placed into the double-
integer word %R00208/%R00209 (for Parameter 1).
Figure 189
In the example above, when switch %I00001 is closed, the Binary Coded Decimal (BCD)
value in BCDINP (%I00017-%I00032) from a BCD Operator Input device is converted to an
integer value (by the BDC4 TO INT instruction), and the integer value is placed in register
%R00150. Next, %R00151 is cleared to zero by the BLK CLR instruction. Note that on the
output of the BCD4 TO INT instruction, %R00150 is a single integer value. However, when
%R00150 is used as an input (IN1) for the double integer Multiply instruction (MUL DINT),
the CPU automatically combines it with the next %R address (%R00151) to form a double-
integer value. Word %R00150 becomes the Least Significant Word, and %R00151 becomes
the Most Significant Word in this double-integer word. The MUL DINT instruction multiplies
the value in %R00150/%R00151 by 1000 and places the result in double word
%R00208/%R00209 (DBL_WRD).
When used this way, %R00151 is called an “implied address” since it is not shown on the
screen. Be aware that you must not use %R00151 for any other purpose (it should be held
to a value of zero); otherwise, the value placed into %R00150 from the BDC4 to INT
instruction would be altered. The same principle applies in the case of double word
%R00208/R00209. Here, the use of %R00209 is implied by the fact that %R00208 is
displayed as the output of the Double Integer Multiply (MUL DINT) instruction. So %R00209
should be reserved for this use only.
In this rung, the MUL DINT instruction performs two functions: (1) it converts the value in
%R00150 from single integer form to double integer form, and (2) it scales the value in
%R00150/%R00151 by multiplying it by 1000. If scaling had not been desired, a value of 1
would be used instead of 1000 at IN2 of the MUL DINT instruction; this would provide
conversion to double integer without changing (scaling) the value.
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