Limiting Frequency Command/Run Command; Limiting Frequency Command - Hitachi WJ Series User Manual

Chapter 9

9.4 Limiting Frequency Command/RUN Command

9.4.1

Limiting Frequency Command

 How to limit the range of the frequency command?
Q
 How to set a lower limit on the frequency command value to prevent the flow rate from
becoming too low?
 How to control the upper limit of the frequency command value as a system?
 The frequency limit function allows you to place upper and lower limits on the frequency
A
command.
 This function limits any frequency commands that fall outside the set range of the frequency
limit.
 The frequency limit function is disabled when set to 0 Hz.
 Be sure to set the frequency limit function so that the upper limit does not exceed the maximum
!
frequency setting. Please note that inconsistent settings may trigger a warning message.
 When configuring the frequency limit function, start by setting the "Upper frequency limit
*1
[A061] ".
Be sure that setting should be that the "Upper frequency limit [A061]
"Lower frequency limit [A062]
 Although "Jogging frequency [A038]" can be set outside the range of the frequency limit
function, the actual output is limited according to the frequency limit function.
 Be sure to set "Output frequency setting or monitor [F001]
15 so that they remain within the upper and lower limits.
Code
Upper
*1
[A061]
frequency limit
Lower
*1
[A062]
frequency limit
*1. "2nd-motor control [SET]" target parameter. The second control parameter is also subject to setting.
■ Example of applying upper and lower frequency limits
Output frequency [Hz]
Maximum
frequency
[A004]
[A061]
[A062]
*1
".
Item
Sets the upper limit of the frequency
command value.
Sets the lower limit of the frequency
command value.
0 VDC 10 VDC
20 mA
4 mA
*1
" and multi-speed commands 1 to
Description
As shown in the figure to the left, after applying
upper and lower limits, when a frequency
command that is input using an analog voltage
or current signal falls outside the upper and
lower limits, the values become the frequencies
set in [A061] and [A062].
Frequency
command
9-4-1
Inverter Functions
*1 " is greater than the
Data
0.00,
Lower frequency limit to
Maximum frequency (Hz)
0.00,
Minimum frequency to
Upper frequency limit (Hz)