The encoder simulation output is derived directly in hardware from the Drive position feedback interface in the drive and the output is derived from the

input with negligible delay. The ratio between the input at the Drive position feedback interface and the output is either unity or a limited number of

binary divider ratios (see Encoder Simulation Hardware Divider (C32)). 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 (C33) = 0 the marker output is derived directly from the

marker input. If Encoder Simulation Hardware Marker Lock (C33) = 1 the incremental output signals are adjusted on each marker event so that the A

and B are high with an AB 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, 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 Pulses Per

Revolution (C35) with a minimum delay of 250 μs which may be extended if Encoder Simulation Sample Period (C30) is set up for a longer sample

period. Note that the number of output pulses per revolution apply to a quadrature (AB) type device. The output is derived by applying a ratio and

output counter roll-over limit defined by Encoder Simulation Output Pulses Per Revolution (C35) as shown below. The output marker is produced

when the output counter is zero.

Figure 8-7 Lines per rev mode

Source position

(65536 counts per

revolution)

If Drive Encoder Position (J53) is selected as the source and Encoder Simulation Incremental Mode Select (C34) = 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. 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 Drive position feedback interface.

If Drive Encoder Position (J53) is selected as the source and Encoder Simulation Incremental Mode Select (C34) = 1 then the encoder simulation

output only follows the changes of source position. At power-up, on device initialization and a marker event no additional pulses are produced to give

the absolute position of the device related to zero position. The encoder simulation output markers is not synchronized to the source marker.

If a source other than Drive Encoder Position (J53) is selected Encoder Simulation Incremental Mode Select (C34) has no effect and the encoder

simulation system always operates in absolute mode.

2: Ratio

The encoder simulation is derived in the same way as described previously for Encoder Simulation Mode (C31) = 1 (i.e. lines per rev mode), except

that different parameters are used to set up the system giving more flexibility as shown below.

Figure 8-8 Ratio mode

Source position

(65536 counts per

revolution)

With the default settings (Encoder Simulation Numerator (C36) = 65536, Encoder Simulation Denominator (C37) = 65536 and Encoder Simulation

Output Roll-over Limit (C38) = 65535) the output produces a state change each time the source parameter changes by one. The numerator and

denominator can be changed to provide a different ratio between the source and the output. Output markers are produced each time the output

counter is zero and the counters are synchronised in the same way as for lines per rev mode. It is possible to control the roll-over limit of the output

counter and hence the rate at which output markers are produced using Encoder Simulation Output Roll-over Limit (C38). For example if the ratio is

set to 1024/ 65536 and the roll-over limit is 1023 then one output marker is produced for every 1024 lines of output incremental signals. If the roll-over

limit is changed to 512, then two output markers are produced for every 1024 lines of output incremental signals.

E300 Design Guide

Issue Number: 1

Electrical

Getting

User Menu A Commissioning

installation

started

Encoder Simulation

Output Pulses Per

Revolution(C35) / 4

Encoder Simulation