Control Techniques Digitax ST - Page 31

Parameter
structure
Keypad and
display
Parameter x.00
Parameter
description format
Advanced parameter
descriptions
Serial comms
protocol
Electronic
nameplate
Performance
Menu 1
Digitax ST Advanced User Guide 31
Issue Number: 1 www.controltechniques.com
Although most parameters can be controlled from analog inputs, these two parameters are a special case in that if an analog input is directed to one
of these parameters, the scan rate of that analog input is increased to 250μs as long as:
1. The reference must be derived via Pr 1.36 or Pr 1.37
2. The analog inputs must be in voltage mode with zero offset
3. Bipolar mode must be used or unipolar mode with the minimum speed (Pr 1.07) set to zero
4. No skip bands are enabled, i.e. Pr 1.29, Pr 1.31 and Pr 1.33 must be zero.
5. The jog and velocity feed-forward references must not be enabled.
These are special parameters when a non-bit type quantity uses these parameters as a destination (not just from analog inputs). The scaling and
limiting applied is as described with Pr 1.08 on page 25.
See Pr 1.09 on page 26.
This parameter indicates the velocity feed forward reference when position control is used (see section 5.15 Menu 13: Position control on page 166).
This bit indicates that the position controller has selected the velocity feed forward as a reference for the drive.
1.36 Analog reference 1
1.37 Analog reference 2
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
111 1
Range ±SPEED_FREQ_MAX rpm
Default 0
Update rate 4ms write
1.38 Percentage trim
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
21 1
Range ±100.00 %
Default 0.00
Update rate 4ms read
1.39 Velocity feed forward
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
1111
Range ±40,000.0 rpm
Update rate 4ms read
1.40 Velocity feed forward select
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
1 111
Update rate 4ms write