[etherlab-users] Beckhoff AX5000 update rate

Hugh Sparks hugh at csparks.com
Tue Jan 28 16:56:10 CET 2020

I'd like to operate one of these drives with a master update rate of 1kHz.
An earlier posting on this list from suggests that 1kHz is possible:


Tom Wong-Cornall on 10/31/2019.
Subject: Re:[etherlab-users]RV: AX5000 fault synchronization


[sync0] There are fixed options for this. 250us is the slowest you can set it, but perfectly fine for 1kHz.


- Sync0 + Sync1 timer values *must* add up to your cycle time (imposed and checked by AX5000's internal logic).


The slowest OpMode in the ESI reads:

	<Desc>Sync cycle time: 250┬Ás</Desc>
	<CycleTimeSync1 Factor="-1">0</CycleTimeSync1>

At first, I thought this meant that the drive needed a sample period of 250uSec.
But CycleTimeSync1/@Factor=-1 implies that the sync1 shift time should be 750uSec.

So if "Sync0 + Sync1 timer values *must* add up to your cycle time", is
OpMode "DcSync250" the correct choice for a 1kHz update rate?

Since I'll be fighting with SERCOS to get the drive started, I want to make sure the basics are right.


H. Sparks

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