Control Techniques Digitax ST - Digital Speed Reference; Analog Reference; Analog Outputs; Digital Inputs and Outputs

Parameter
structure
Keypad and
display
Parameter x.00
Parameter description
format
Advanced parameter
descriptions
Serial comms
protocol
Electronic
nameplate
Performance
220 Digitax ST Advanced User Guide
www.controltechniques.com Issue Number: 1
8 Performance
8.1 Digital speed reference
Table 8-1 Accuracy and resolution
*0.01% of the reference
8.2 Analog reference
Table 8-2 Update rates
* Analog input 1 is subject to a window filter as defined in Pr 7.26.
Table 8-3 Resolution
*16 bit plus sign as a speed reference, resolution = Pr 7.26 x 500 x 10
3
.
8.3 Analog outputs
Table 8-4 Resolution and update rate
*When sourced from Pr 3.02, Pr 4.02, Pr 4.17 and Pr 5.03.
8.4 Digital inputs and outputs
Table 8-5 Response times
*Software only
8.5 Current feedback
Accuracy: 5% worst case, 2% typical
Resolution: 10 bit plus sign
Full scale resolution is equivalent to the OI.AC trip level of 381% of
Maximum rated current or 222% of the Current Scaling value Kc. For
information on the values of the Maximum rated current and Current
Scaling value for a drive, see Table 5-3 on page 68.
8.6 Bandwidth
The following bandwidth values are for 12kHz PWM switching
frequency:
8.6.1 Speed loop
The speed loop bandwidth is 160Hz
8.6.2 Current loop
The current loop bandwidth is 1100Hz for the 3dB point, and 400Hz for
the 45°point.
1. The gain characteristic and associated 3dB point is most useful
where drive is used in an application where the current controller is
not included within an outer control loop.
2. The phase characteristic and associated 45° point is most useful
where the current controller is used within an outer control loop such
as a speed controller. The phase delay of the current controller has a
limiting effect on the response of the outer loop.
Preset Precision
Accuracy 0.01%* 0.01%*
Resolution 0.1rpm 0.001rpm
Analog input Pr 1.36 & Pr 1.37 Pr 4.08 Pr 3.22 Other
1 250μs* 4ms* 250μs* 4ms*
2 and 3 250μs 250μs 250μs4ms
Analog input Resolution
1 16 bits plus sign*
2 and 3 10 bit plus sign
Resolution (voltage mode) 10 bit plus sign
Resolution (current mode) 10bit
Update rate 4ms
Update rate (high speed update - voltage mode
only)*
250μs
Switching
frequency
Terminals
Pr 6.35 / Pr 6.36
(Limit
switches)
Other
All 24-26 as input 250μs4ms
All 24-26 as output 4ms 4ms
All 27-29 250μs4ms
All 31 (enable) - 4ms*
All 31 (disable) - <100μs
All
Relay output
closing
4ms* 4ms*
All
Relay output
opening
4ms* 4ms*