ElmoMC SimplIQ Software Manual - Manual (Page 14)

SimplIQ Software Manual Communication with the Host
MAN-SIMSW (Ver. 1.4)
2-5
2.5 SimplIQ Drive Peripherals
2.5.1 Position Decoders
The SimplIQ drive includes two position decoders — main and auxiliary — which are
similar to each other. Both decoders are timed (through timer sets A and B) for accurate
speed information. A position decoder measures quadrature or pulse/direction. The
maximum counting rate of a decoder is 20 MHz, without an input filter. If an input filter
is applied, the maximum pulse rate is reduced (this is fully explained in the EF[N]
command in the
SimplIQ Command Reference Manual).
The encoder input is not protected: no hardware identifies illegal transitions. Exceeding
the maximum pulse rate causes a loss of counts that cannot be detected.
2.5.2 A/D Converter
The A/D converter samples the following signals:
ƒ
Ia, Ib, Ic The three phase currents, sampled simultaneously
ƒ Ain,ref The analog input and the reference voltage, sampled simultaneously to
form a differential measurement
ƒ Bus voltage Sampled to correct the current loop gain
The resolution of all the measurements is 12 bits, and, in practice, the last bit is noisy. The
motor currents are measured offset-free, as the result of a special measurement
mechanism. Due to electronic inaccuracies in the
SimplIQ drive circuits, the analog inputs
cannot avoid an offset, which can be corrected to a resolution of about 5 millivolts, using
the AS[1] parameter. AS[1] can correct offsets within the limited resolution range of
5 to 10 millivolts. This means that, for example, if AG[2]=10,000, the offset correction
quality of the speed analog reference will be limited to about 100 counts/second.
2.5.3 Digital Inputs
In the Harmonica, the drive’s six digital input connector pins are routed to a digital input
port. In addition, two pins (5 and 6) are routed to high-speed capturing input for main
and auxiliary homing. Special functions — such as Enable, Stop, RLS and FLS — can be
associated with the digital input pins (refer to the IL command in the
SimplIQ Command
Reference Manual). Digital Input is handled differently in the other drives, see their
Installation Guide for details.
The digital input response time is limited by the speed of the optical couplers and the
input filters. The encoder index and home input are filtered similarly to the position
decoders. The timing of the position decoder filters is explained in the EF[N] command
section in the
SimplIQ Command Reference Manual.
The other digital inputs are filtered in the software only. The timing of the software
filtering is explained in the IF[N] command section in the
SimplIQ Command Reference
Manual.
The use of digital inputs is detailed in Chapter 12 of this manual.