Errors from Compumotor-Based Oscillation Camera

• Connection problems

  The ADX software talks to the CompuMotor using the ccd_bl_cm program. If this program is unable to connect to CompuMotor, or loses the connection, an error "Beam Line Control connection DROPPED" is shown. To fix a connection problem, first check setup items:

  • when using a serial connection (F3) - check that the serial port can be used by an ordinary user: type "ls -l /dev/ttyS1". The permission string returned should be "crw_rw_rw_". If it is "crw_rw____", you need to add read/write permission for everyone: as superuser, type "chmod a+rw /dev/ttyS1".

  • When using the Ethernet (A1, F1, F2) - type "/sbin/arp -a" and check that the list returned has two entries for a1cm1 and a1cm2 (at A1; f1cm# at F1 and f2cm# at F2) which contain the item "PERM". If the entries are missing or have "incomplete" instead of "PERM", you need to add them to the table: as superuser, type "/etc/rc.d/init.d/compumotor_arp".

  If you still get the error, do a power cycle on the CompuMotor equipment.

• Status checking

  For each oscillation the controller checks five conditions:

  1. CCD shield (garage door) has been raised, and shutter is initially closed

  2. Shutter is opening and closing at the proper times

  3. Collimator ion chamber (Icol) has sufficient counts

  4. Servo motor is operating within specified parameters

  5. HEP signal from CESR is present

  An appropriate error message is generated if an error is detected, and will appear in a pop-up window on the computer where the ADX data collection software is running.

• What to do about error messages

  "safety shield down or shutter open" - check that shield is raised. If shield is OK, type "closes" in OpsTerm window on station computer. If error still occurs, there is a hardware problem with the shield or the shutter. Look for loose wires, etc. in shield mechanism; see below for things to try for a shutter problem.

  "counts in collimator too low" - self-explanatory. The threshold level for 'low counts in Icol' can be adjusted with a pot on the side of the gray interface box located in the center of the Compumotor assembly.

  "shutter left open or failed" - if the shutter has been opened by "opens" on the station computer, close it by typing "closes" in OpsTerm window. If this is not the problem, first cycle power on the shutter control box. If the error persists check the cabling and power to the shutter control box and also the 5 pin hex connector on the side of the shutter housing.

  "spindle motor failure" - usually indicates that the servo motor is no longer operating with the required accuracy. Cycle the power on the Isobar power strip on the Compumotor assembly (on the wall inside the hutch). Then restart the data collection. If the error persists, it is time to call a MacCHESS person.

  "no beam" - no HEP signal is present, i.e. the CESR status is not "RUN IN PROGRESS". If you want to take images anyway, disconnect the cable carrying the HEP signal; this condition appears the same as HEP in progress to CompuMotor.