Parameter
structure
Keypad and
display
Parameter x.00
Parameter description
format
Advanced parameter
descriptions
Serial comms
protocol
Performance
Menu 2
Mentor MP Advanced User Guide 37
Issue Number: 4 www.controltechniques.com
The time taken in seconds for the ramp output to change by speed (Δw*) is given below. Two cases are given because the total ramp time must be
calculated with a different equation depending on whether the acceleration is able to reach the selected ramp rate (A1) or not. If the required change
is small the selected ramp rate is not reached and the ramp does not include the central linear ramp region. If the required change is larger the ramp
does include the central linear region as shown in the diagram above.
Speed
Δw*
linear
= 1000 x J / A1
2
where:
A = selected ramp rate
J = Pr 2.07
If the required change is less than Δw*
linear
then T
Ramp1
should be used, but if the speed change is greater or equal to Δw*
linear
T
Ramp2
should be
used.
T
Ramp1
= 2 √ (Δw* x Pr 2.07 / 1000)
T
Ramp2
= (Δw* x A / 1000) + (Pr 2.07 / A)
The default values for the ramp rate and S ramp acceleration limit have been chosen such that for the default maximum speed, the curved parts of
the S ramp are 25 % of the original ramp if S ramp is enabled. Therefore the ramp time is increased by a factor of 1.5.
The acceleration rate is selected as follows.
0 Ramp rate selection by terminal input
1 - 8 Ramp rate defined by parameter number, i.e. 1 = Pr 2.11 {SE03, 0.24}, 2 = Pr 2.12, etc.
9 Ramp rate selection by Pr 1.50
When Pr 2.10 is set to 0 the acceleration ramp rate selected depends on the state of bit Pr 2.32 to Pr 2.34. These bits are for control by digital inputs
such that ramp rates can be selected by external control. The ramp rate selected depends on the binary code generated by these bits as follows:
When Pr 2.10 is set to 9 the appropriate acceleration rate is automatically selected depending on the value of Pr 1.50, and so an acceleration rate can
be programmed to operate with each reference. Since the new ramp rate is selected with the new reference, the acceleration applies towards the
selected preset if the motor needs to accelerate to reach the preset.
2.10 Acceleration rate selector
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
111
Range 0 to 9
Default 0
Update rate 4 ms read
Pr 2.34 Pr 2.33 Pr 2.32 Ramp defined by
00 0Pr 2.11 {SE03, 0.24}
00 1 Pr 2.12
01 0 Pr 2.13
01 1 Pr 2.14
10 0 Pr 2.15
10 1 Pr 2.16
11 0 Pr 2.17
11 1 Pr 2.18
To Next Page
Loading...
Need help?
General
