Hitachi NJI-350B - Manual (Page 188)

Chapter 5 Instruction Specifications
5-138
Item number FUN instructions-13 Name PWM Frequency on-duty changes
Ladder format Condition code Processing time ( µs) Remark
R7F4 R7F3 R7F2 R7F1 R7F0 Average Maximum
FUN 148 (s) DER ERR SD V C
↕ z z z z
Instruction format Number of steps 173 
Condition Steps
FUN 148 (s) — 3
Bit Word Double word
Usable I/O
X Y
R,
M
TD, SS,
CU, CT WX WY
WR,
WM TC DX DY
DR,
DM C
o
nstant
Other
s
Argument (PWM output
number)
{
s+1
Argument (Frequency
value)
{
s+2
Argument (On-duty
value)
{
Function
PWM output number: H01 to H04
**: Disable area
Frequency: 10 to 2000 (Hz)
*: If the frequency value is set to less than 10 Hz, it is
internally changed to 10 Hz. The S parameter is also
rewritten.
On-duty value:
With auto correction – Depends on the frequency used.
Without auto correction – 0 to 100 (%)
Auto correction is executed when the value corresponding to
the CPU model is specified in WRF06B.
Caution: There will be a slight error even if correction setting
is performed
• Sets the frequency value and on-duty value of the PWM output number specified by the on-duty value and the specified
frequency value.
• Sets the frequency value in Hz.
Example: To set a frequency of 1 kHz, set 1000 (H3B8) as internal output.
• Sets the on-duty value in %.
Example: To set an on-duty of 80 %, set 80 (H50) as internal output.
• When the on-duty is set to be auto-corrected, the effective range of the on-duty is calculated using the following expressions.
On-duty lower limit value (%) = Hardware delay time ( µs) x Frequency used (Hz) x 10 -4
On-duty upper limit value (%) = 100 − Hardware delay time (µs) x Frequency used (Hz) x 10 -4
If the CPU model is EH-***DRP and the PWM output is 2 kHz,
On-duty lower limit value = 50 x 2000 x 10 -4 = 10 %
On-duty upper limit value = 100 − (50 x 2000 x 10 -4 ) = 90 %
Thus, the effective range of the on-duty will be 10 % to 90 %.
S
15 0
S + 1
Frequency values
S + 2
On-duty value
PWM number **
8 7
FUN 148 (s
)