Experimental Physics and
Industrial Control System

"Pearson, Matthew R." <[email protected]> · Fri, 21 Jun 2013 09:31:57 -0400

Hi Christian,

Is there a reason this is implemented using basic records and streamDevice, and not using the motor record and an Asyn motor driver? If you had an Asyn motor driver, you would be able to use the motor record, which has fields such as DMOV (done moving), MOVN (currently moving), etc… 

It also supports ca_put_callback for you, so you can write a new position and wait for move completion before the function/database put returns.

However, perhaps the controller is so simple it wasn't worth doing a motor driver for it? But even with simple controllers I have found that it's often worth developing an Asyn motor driver for it just to take advantage of all the features that the motor record provides. Not to mention the fact that you maintain a consistent interface for all motors.

Cheers,
Matt

On Jun 21, 2013, at 5:52 AM, Christian Pauly <[email protected]> wrote:

> Ok, i see.
> 
> But still:
> How can i get then information if the motors are running at the moment, 
> or not. Without doing periodic scans on the PACT fields ??
> 
> 
> On 06/21/2013 11:39 AM, Ralph Lange wrote:
>> Hi Christian,
>> 
>> On Fri Jun 21 2013 11:07:38 GMT+0200 (CEST), Christian Pauly
>> <[email protected]>  wrote:
>>> No, only one motor can move at a time.
>>> But i thought it is "bad style" to do this synchronous with such large
>>> delays ? ( I had to define huge timeouts in the protocol to get it
>>> work...)
>> 
>> This rule of not doing synchronous device support for devices with long
>> delays applies to writing device support.
>> 
>> If you are using StreamDevice (which I assume), your device support is
>> not synchronous - StreamDevice and ASYN support below are working
>> asynchronously and take care of the gory details for you.
>> 
>> The port that you are communicating with will be locked while a protocol
>> (like your move command) is running. But that is fine if the device can
>> only use one motor at a time.
>> 
>> Cheers,
>> ~Ralph
> 
> 
> -- 
> Dr. Christian Pauly
> Bergische Universität Wuppertal
> Fachbereich C - Physik
> Gaußstraße 20, D-42119 Wuppertal
> Tel: +49 (0)202 439-2632,
> Fax: +49 (0)202 439-2662
> 
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System