From ce53b5b9de5c3ef2378e09d25fd3234ad950de75 Mon Sep 17 00:00:00 2001 From: Ron Sluiter Date: Thu, 15 Apr 2010 14:44:36 +0000 Subject: [PATCH] - Update MM4000 status update limitations. - Document PM500 LSIZE setting. --- motorApp/NewportSrc/README | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/motorApp/NewportSrc/README b/motorApp/NewportSrc/README index ed38cbf5..709f1cf3 100644 --- a/motorApp/NewportSrc/README +++ b/motorApp/NewportSrc/README @@ -97,3 +97,29 @@ Setting and saving an ESP100 for use with a DC servo motor driven stage (e.g., 1QM 1 SM + + +Newport MM4000 +============== + +The MM4000 controller has an approximately 50ms delay before it responds to a +status query. Hence, it is impossible to get more that a 20 Hz update rate +from the MM4000; 7 or 8 Hz is attainable. This 50ms delay exists with both +RS232 and GPIB communication interfaces. + + +Newport PM500 +============= + +The PM500 has high and low speed loops. Since the EPICS PM500 device driver +does not set any of the low speed parameters (i.e., LSIZE, LACCEL, LDECEL, LV), +the low speed loop feature may interfere with EPICS setting the slew velocity. +I recommend preventing the PM500 from ever using the low speed velocity loop by +setting the Low Speed Loop Threshold (LSIZE) to the motor record's Retry +Deadband field (RDBD). + +The LSIZE can be set from the EPICS motor record by entering the PM500 command +in the record's INIT field. LSIZE is in units of either um or arc-sec. For +example, if your RDBD = 0.123 mm, then set the INIT field to "LSIZE 123.0". + +