Emerson SI-Universal User Manual page 87

(1x.089)). The hardware mode only produces an output with AB, FD, FR, SC, SC Hiperface, SC
EnDat or SC SSI type devices.
It should be noted that with a SINCOS source device, the output is based on the zero crossings of
the sine wave inputs and does not include interpolation. If Encoder Simulation Hardware Marker
Lock (1x.090) = 0, the marker output is derived directly from the marker input. If Encoder Simulation
Hardware Marker Lock (1x.090) = 1 the incremental output signals are adjusted on each marker
event so that the A and B markers are high with an AB type output, or alternatively F is high with an
FD or FR type output.
Marker locking is not recommended if the number of lines per revolution of the encoder simulation
source combined with the ratio does not give an encoder simulation output with a multiple of 4
counts per revolution (i.e. between each output marker event) for AB signals, or a multiple of 2
counts for FD or FR signals, because this causes a count error in the system receiving these
signals.
The input marker pulse width is not adjusted to take account of the divider ratio, but is simply routed
from the input to the output. Therefore the output marker pulse becomes shorter with respect to the
output incremental signals as the divider ratio is increased.
1: Lines Per Rev
The encoder simulation output is derived via software from the selected source with a resolution
defined by Encoder Simulation Output Lines Per Revolution (1x.092) with a minimum delay of 250
µs which may be extended if the Encoder Simulation Sample Period (1x.087) is set up for a longer
sample period. Note that the number of output lines per revolution apply to a quadrature (AB) type
device, and that if FD or FR mode are selected the number of lines per revolution are 2 x Encoder
Simulation Output Lines Per Revolution (1x.092). The output is derived by applying a ratio and
output counter roll-over limit defined by Encoder Simulation Output Lines Per Revolution (1x.092)
as shown below. The output marker is produced when the output counter is zero.
If P1 Position (1x.029) is selected as the source and Encoder Simulation Incremental Mode Select
(1x.091) = 0 then the input and output counters are synchronised at power-up and when the P1
position feedback interface becomes initialized, so that the output marker is synchronised with zero
position for the P1 position feedback interface. For devices that support a marker, the effect of the
marker on the position can be selected using P1 Marker Mode (1x.031).
At power-up and on device initialization, there will be a step change in position from zero to the
actual position from the device and the pulses necessary to make this change are produced at the
encoder simulation output. If a marker event occurs that causes a step change in position, again
the necessary pulses will be produced for this change of position.
Where large sudden changes occur the maximum output frequency is limited to 500 kHz, and so it
may take some time for the output position to reach the input position.
This mode of operation gives an initial position change from zero position and then follows all
changes of position from that point onwards, and may be used to follow the absolute position of the
device connected to the P1 position feedback interface.
If P1 Position (1x.029) is selected as the source and Encoder Simulation Incremental Mode Select
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SI-Universal Encoder User Guide
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