Omron CQM1H - PROGRAM Programming Manual page 334

Conversion Instructions
Description
DM 6144 to DM 6655 cannot be used for R.
SCL3(––) is used to linearly convert a 4-digit BCD value to 4-digit signed
hexadecimal. SCL3(––) converts the BCD value according to a specified lin-
ear relationship. The conversion line is defined by the y-intercept and the
slope of the line specified in the parameter words P1 to P1+2.
When the execution condition is OFF, SCL3(––) is not executed. When the
execution condition is ON, SCL3(––) converts the 4-digit BCD value in S to
the 4-digit signed hexadecimal value on the line defined by the y-intercept (0,
P1) and the slope (P1+2 ÷ P1+1) and places the result in R. The result is
rounded off to the nearest integer.
The content of S can be 0000 to 9999, but S will be treated as a negative
value if CY=1, so the effective range of S is actually –9999 to 9999. Be sure to
set the desired sign in CY using STC(40) or CLC(41).
Parameter words P1+3 and P1+4 define upper and lower limits for the result.
If the result is greater than the upper limit in P1+3, then the upper limit is writ-
ten to R. If the result is less than the lower limit in P1+4, then the lower limit is
written to R.
Note The upper and lower limits for a 12-bit Analog Input Unit would be 07FF and
F800.
The following table shows the functions and ranges of the parameter words:
Parameter
P1 x-intercept (signed hex.)
∆X (BCD)
P1+1
∆Y (signed hex.)
P1+2
P1+3 Upper limit (signed hex.)
P1+4 Lower limit (signed hex.)
Note Do not set 0000 for ∆ X (4 digits BCD) in the second word (P1+1). The con-
tents of P1+1 is used for division and correct conversion cannot be obtained
when dividing by 0000. Correct results also cannot be obtained if a hexadeci-
mal value is used. Always use BCD data between 0001 and 9999 for P1+1.
The following diagram shows the source word, S, converted to R according to
the line defined by the point (0, P1) and slope ∆ Y/ ∆ X.
Value after conversion
(Signed hexadecimal)
Upper limit
Y-intercept
Lower limit
Function
8000 to 7FFF (–32,768 to 32,767)
0001 to 9999
8000 to 7FFF (–32,768 to 32,767)
8000 to 7FFF (–32,768 to 32,767)
8000 to 7FFF (–32,768 to 32,767)
∆X
R
S
Section 5-20
Range
∆Y
Value before con-
version (BCD)
309