Performance; Digital Speed Reference; Analog Reference; Analog Outputs - Control Techniques Digitax ST Advanced User's Manual

Parameter Keypad and
structure display
8

Performance

8.1

Digital speed reference

Table 8-1 Accuracy and resolution
Preset
Accuracy 0.01%*
Resolution 0.1rpm
*0.01% of the reference
8.2

Analog reference

Table 8-2 Update rates
Analog input Pr 1.36 & Pr 1.37
1 250μs*
2 and 3 250μs
* Analog input 1 is subject to a window filter as defined in Pr 7.26.
Table 8-3 Resolution
Analog input
1 16 bits plus sign*
2 and 3 10 bit plus sign
*16 bit plus sign as a speed reference, resolution = Pr 7.26 x 500 x 10
8.3

Analog outputs

Table 8-4 Resolution and update rate
Resolution (voltage mode)
Resolution (current mode)
Update rate
Update rate (high speed update - voltage mode
only)*
*When sourced from Pr 3.02, Pr 4.02, Pr 4.17 and Pr 5.03.
220
Parameter description
Parameter x.00
format
Precision
0.01%*
0.001rpm
Pr 4.08 Pr 3.22 Other
4ms* 250μs* 4ms*
250μs 250μs 4ms
Resolution
10 bit plus sign
10bit
4ms
250μs
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8.4

Digital inputs and outputs

Table 8-5 Response times
Switching
Terminals
frequency
All 24-26 as input
All 24-26 as output
All 27-29
All 31 (enable)
All 31 (disable)
Relay output
All
closing
Relay output
All
opening
*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.
3
.
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.
Electronic
protocol nameplate
Pr 6.35 / Pr 6.36
(Limit
switches)
250μs
4ms
250μs
-
-
4ms*
4ms*
Digitax ST Advanced User Guide
Issue Number: 1
Performance
Other
4ms
4ms
4ms
4ms*
<100μs
4ms*
4ms*