(Forwarding an earlier reply back to the list; it got stuck in moderation due 
to signature images out of my control.)

----

No, not without deactivating the master and reconfiguring it.  But for the 
master to know that it needs to do that, you'd have to have your safety routine 
communicate a fault back to the master, in which case you can tell it to change 
its normal PDO output to a safe value instead of stopping communication.  
Usually this will take at least one cycle to get the status update, so you 
probably can't avoid sending the "wrong" value at least once.

Meanwhile the servo slave itself, when it detects a fault condition, should go 
into a state where it ignores whatever values the master is sending (unless it 
considers them "safe" for its fault condition), bridging the time between when 
the fault is detected and when the master notices and updates its outputs.

(If this isn't your own slave device then you should probably be asking the 
slave vendor how to do this sort of thing properly.)

---- 


Gavin Lambert
Senior Software Developer

 


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From: BUSSIERES Vincent
Sent: Thursday, 17 September 2020 07:55
To: etherlab-users@etherlab.org
Subject: [Etherlab-users] dynamic PDO unmapping

Hello, 

I'd like to unmapp PDOs dynamically or to stop sending PDO data to a particular 
slave. 
My EtherCAT network includes 6 slaves, among them digital inputs / outputs 
modules and servodrives modules.
I have developped safety functions embeded into the servodrives modules. For 
instance, in case of emergency stop, the embeded program reads digital safety 
emerency input and configures a torque setpoint to stop the motor very quickly. 
The problem is that EtherCAT master sends PDO frames continuously to all the 
slaves, in particular torque setpoint PDO to servodrive. Therefor the setpoint 
configured in embeded program is replaced by the one sent by EtherCAT master.
 
So I'd like to know if it is possible to stop sending temporarly PDO to a 
particular slave or unmapp these PDOs.
 
Best regards
 
Vincent BUSSIERES
Responsable Technique Logiciel
 

ZE Ma Campagne
36, Impasse Félix Nadar
16000 ANGOULEME
Tel: 33 (0)9.72.40.35.08
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