piervali

Curt, thanks for quick reply. So I guess my wished sequence of actions should be implemented in a buffered program. An upper programming layer of us ( "EPICS" ) sends "online" command to the PowerPMAC by SSH. I tried this online command: cpx jog/1 PowerBrick[0].GpioData[0].17.1=1 dwell2000 jog1^10000 ... but it does not work as "jog1^10000" starts imediately and does not wait for the "dwell2000" 2 seconds delay to finish. I have two practical quetions now: how can I program a delay in a buffered program ? (delay and dwell commands did not work for me) in case I use the "BrakesOffDelay" with a "j/" command, how can I automatically trigger the following "j^10000" command after Brakes have been released ? Some practical example would be welcome. Thanks to all. PV

Hi to all from Paul Scherrer Intitute, I did today some tests with the "Brakes control" function. We have some applications where brakes are used to keep firmly axis in position while removing motor current for cooling purposes in typical scientific applications. We already used this break control with other motion controllers brands. I believed that I could do the same with Delta Tau PPMAC, but I just noticed a strange misbahaviour. Here down I write more details. The questions will be: a) did I setup correctly the brake control ? b) if yes, if there a workaround to the problem ? c) if not, I will not use the brake function and write a specific buffered program instead... :-( Problem description: Note: for my test I did not use real brakes installed on motor shaft. The latter is free to rotate and I monitor the digital output separately. I did use the PowerPMAC IDE and wrote commands in terminal window: motor[1].pBrakeOut=PowerBrick[0].GpioData[0].a // set brake pointer to GPIO register motor[1].BrakeOutBit=17 // set bit 17 as GPIO output pin coonected to my brakes system motor[1].BrakeOffDelay=1000 // set delay to 1000 ms for brakes release delay after "j/" command (long enough for my tests purpose) motor[1].BrakeOnDelay=1000 // set delay to 1000 ms for brakes on after "dkill" command (long enough for my tests purpose) #1j/ // closing the servo-loop. What I observe: Current set immadiately in motor. after 1000, ms GPIO dig output 17 set to "1" and brakes released. dkill // delayed kill. GPIO dig output 17 set to 0 instantly (brakes on). After 1000 ms servo-loop and motor current removed. So far my tests where satisfacctory ... but the following test behaves not like I would expect to: Instead of just closing the servo-loop with "#1j/" command, I want to directly order a motion with "#1j^10000" command. Here the result: #1j^10000 // What I observe: current set and immediate motion start !!... After 1000 ms, GPIO dig output 17 set to "1" and brakes released. Of course I do not want motion controller tries to move the motor while brakes are still ON !! So I think there is a little misconception problem in this brakes control function (or a firmware bug or whatever...). I believe the right behaviour should be:[/font] #1j^10000 // motion order... immediately, should servo-loop be closed... but WITHOUT motion !! also immediately, should digital output 17 go to 1 to release brakes after the "BrakesOffDelay" time, the desired motion could start In this case "BrakesOffDelay" is more related to the minimum time brakes really need to be completely released after digital output if set to 1 (may depends on a list of processing delays... one among them: removing current in a coil if not instantaneous !!). In software reference, is described as the time needed to close the loop before brakes release. This has also sense, but the main point of my post: the necessary time for brakes to fully release since the digital output set is not taken in acount ! (or I did miss something... sorry). I stop here my post and hope to get some feedback... thanks Best regards PV

Hello all, about question 4. of Erik: I am doing config test right now with stepper motor control. I am using AmpEnable feature. Sorry if my question has an obvious answer as I am just beginning using PowerPMAC ;-) Actually it works as I espect for the start of the motion after a "kill" state. AmpEnable is activated and motor moves. Ok but my problem is at the end of the motion: Motor stops. Not absolutely actually as a few steps left or right come out at end point, probably as control loop is still closed. Anyway that is not my exact problem. What I would like is that when motion ends, AmpEnable is automatically set to OFF. I don't want to turn it OFF by programmation or manually with "k" or "Gate3[0].Chan[0].AmpEna=0". Anyone can tell me the config to apply for this ? Thanks PV

Hi Charles, thank you for quick reply. I went already through the training slides. I got enough info to finally make my first setup with stepper motor move with a DeltaTau PowerPMAC. That was thank to actual availables docs and also this two posts you did contribute to: http://forums.deltatau.com/showthread.php?tid=638 http://forums.deltatau.com/showthread.php?tid=768 "Power PMAC User's Manual" at page 116 is probably the "Power PMAC Basic Motor Setup" section you was talking about, and pages 131-139 seems to give the most detailed explanations for a stepper motor configuration. My problem was the one of many "beginners": We follow some instructions in manuals and it does not work because there is a high probability that we did not, or wrongly, program a variable which is decribed at page 874 of manual number 27 ! What I mean is that, for a start, I just prefer a simple recipe, with which a well defined motor setup works at 99% probability. From there then we feel more confident and we may try configurations flavours to better understand the various parameters with a real setup. Now I wonder if exists a nice block diagram showing the full DSPGate3 ASIC data elements. We find parts of it in Traning slides but not a complete one (I mean the big sheet format I am going to hang on my office wall ;-)). Text descriptions of how data flows through the registers needs a too high 3D imagination skills, right ? Thanks and best regards PV

Hello Charles, I can not access this "Power PMAC Basic Motor Setup". Has document been renamed or deleted on your ftp ? Thanks PV