Lenze MCH Series User Manual

Page 64

13435744_EDBMH01_v13

SLEEP BANDWID (SLEEP BANDWIDTH)

This parameter allows the PID feedback signal to determine when drive should "wake

up" when operating in Sleep Mode. In process systems that utilize Integral Gain

(Parameter 78), the drive may cycle in and out of Sleep Mode more often than desired,

due to the Integral function of the PID algorithm.
When SLEEP BANDWIDTH is used, the feedback signal must decrease or increase

(depending on whether the system is normal or reverse-acting) by the programmed

amount before the drive will "wake up". This parameter is set in PID units.
Example:

In a normal-acting system, the PID setpoint is 50 PSI, SLEEP THRESHOLD

is set to 20 Hz, and SLEEP BANDWIDTH is set to 5 PSI. The drive will

enter Sleep Mode when the commanded speed drops below 20 Hz for the

time defined in SLEEP DELAY. The drive will wake up when the feedback

signal drops below 45 PSI (50 PSI setpoint minus 5 PSI bandwidth = 45

PSI), even if the commanded speed is still below 20 Hz.

NOTE:

If SLEEP BANDWIDTH is set to 0, this function is disabled, and the drive will

wake up when the commanded speed exceeds the SLEEP THRESHOLD

plus 2 Hz, as described in Parameters 36 and 37.

TB5 MIN FREQ

This parameter sets the output frequency of the drive that will correspond to the minimum

analog speed reference input (0 VDC or 4 mA). This parameter is used in conjunction

with Parameter 40 - TB5 MAX FREQ to define a speed range that corresponds to the

analog speed reference input (0-10 VDC or 4-20 mA).
40

TB5 MAX FREQ

This parameter sets the output frequency of the drive that will correspond to the maximum

analog speed reference input (10 VDC or 20 mA). This parameter is used in conjunction

with Parameter 39 - TB5 MIN FREQ to define a speed range that corresponds to the

analog speed reference input (0-10 VDC or 4-20 mA).
Example:

The drive is required to operate from 0 to 60 Hz in response to a 0-5 VDC

speed reference signal (rather than the “normal” 0-10 VDC). Because TB5

MAX FREQ is based on a 0-10 VDC (or 4-20 mA) signal, the drive will

operate at half of the TB5 MAX FREQ value if it is given a 5 VDC signal.

Therefore, setting TB5 MAX FREQ to 120 Hz will cause the drive to run at

60 Hz when it is given a 5 VDC speed reference signal.

NOTE:

The drive can be programmed for inverse operation so that as the speed

reference increases, the drive speed will decrease, and as the speed

reference decreases, the drive speed will increase. This is accomplished

by setting TB5 MIN FREQ to the desired maximum output frequency, and

TB5 MAX FREQ to the desired minimum output frequency.

AN INPUT FLTR (ANALOG INPUT FILTER)

This parameter adjusts the filter on the analog input terminals (TB-5A and TB-5B) to

reduce the effect of any electrical noise that may be present on the analog input signals.
This filter works in both PID mode and standard speed control mode. It should be set to

the lowest value that yields acceptable performance, as setting it too high may cause

the drive to react too slowly to signal changes.