EtherCAT
Operating Manual EtherCAT for, PMCtendo DD5 and PMCprotego D
1002906-EN-02
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This is performed via a mailbox SDO access (see
Mailbox Handling [
25]
) to the CAN-
open objects 0x60C2 Subindex 1 und 2.
The subindex 2, called interpolation time index, defines the power of ten of the time value
(e.g. -3 corresponds to 10
-3
, that is millisecond) while the subindex 1 called time units", spe-
cifies the number of units (e.g. 4 for 4 units).
If you want to run a cycle time of 2 ms this can be specified via various combinations,m e.g.
via:
Index = -3, Units = 2
or
Index = -4, Units = 20 etc.
The parameter PTBASE is counted in increments of 250 microseconds inside the device. 2
ms correspond to a PTBASE of 8, for example.
4.7
Recommended cycle time based on the operating modes
With the servo amplifier, the minimum cycle time depends very much of the drive configura-
tion (second actual position value encoder, latching). The analogue evaluation of the drives
should be deactivated, if possible (ANOUT1=0, ANOUT2=0, ANCNFG= -1).
Interface
Cycle time PMCprotego D
Position
³ 0.25 ms (³ 250 µs)
Speed
³ 0.25 ms (³ 250 µs)
Torque
³ 0.25 ms (³ 250 µs)
4.8
Synchronisation based on the cycle time
With all the Pilz servo amplifiers the internal PLLL can compensate a mean deviation from
the cycle time specified by the Mater of up to 1000 ppm. This means, for example that with
a set cycle time of 1 ms the drive can still synchronise itself with a mean deviation in the
cycle time specified by the master of up to +/- 1µs with its internal PLL. The mean deviation
of the cycle time is understood to be the mean length of all cycles.
The servo amplifier enables to report the following jitter in the master cycle time without a
synchronisation error, depending on the set cycle time:
Cycle time >= 1ms → permitted jitter = 320 µs
Cycle time <= 750 µs → permitted jitter = 70 µs
In the second consecutive mater interrupts, outside the permitted jitter, the drive signals a
synchronisation error F28 and/or warning F17. The synchronisation monitoring can be
switched off with the ASCII command SERCSET Bit 17 and 18.
