Using Keithley6487 instrument support in an application

Several files need minor modifications to use Keithley6487 instrument support in an application.

  1. Add the full path to the Keithley6487 support directory to the application configure/RELEASE file:
    Keithley6487=xxxx/modules/instrument/keithley6487/<release>
    Where <release> is the release number of of the Keithley6487 support.
  2. Add stream and asyn support to application database definition file
    The application database definition file must include the database definition files for the stream package and for any needed ASYN drivers. There are two ways that this can be done:
  3. Add the stream and asyn support libraries to the application
    You must link the stream support library and the ASYN support library with the application. Add the following lines:
    xxx_LIBS += stream
    xxx_LIBS += asyn
    before the
    xxx_LIBS += $(EPICS_BASE_IOC_LIBS)
    in the application Makefile.
  4. Ensure that the devKeithley6487.proto StreamDevice protocol file is in a directory in the STREAM_PROTOCOL_PATH list.
  5. Load the Keithley6487 support database records in the application startup script:
    cd $(Keithley6487)      (cd Keithley6487 if using the vxWorks shell)
    dbLoadRecords("db/devKeithley6487.db,"P=<P>,R=<R>,PORT=<PORT>,A=<A>,NELM=<N>")
    You'll have to provide appropriate values for the PV name prefixes (<P> and <R>), the port name (<PORT>) and the device address (<A>). The port name must match the value specified in an ASYN drvxxxxxConfigure command.  The NELM parameter sets the size of the triggered acquisition waveform and defaults to 1000 if not present.

    Here are the salient commands from the example Keithley 6487 application:
    drvAsynIPPortConfigure("L0","moxa01:4002 COM",0,0,0)
    asynSetTraceIOMask("L0",-1,0x2)
    asynSetOption("L0", -1, "baud", "57600")
    asynSetOption("L0", -1, "bits", "7")
    asynSetOption("L0", -1, "parity", "even")
    asynSetOption("L0", -1, "stop", "1")
    asynSetOption("L0", -1, "crtscts", "N")
    dbLoadRecords "db/devKeithley6487.db" "P=$(P),R=1:,PORT=L0,A=-1,NELM=1000"
When the 6487 performs a MEASure? command it silently resets several parameters used by triggered acquisition.   When switching from ‘measure’ to ‘triggered’ acquisition you should process the $(P)$(R)RestoreTriggerSettings record to return the parameters to their desired values.

This module has been tested only with a serial connection to the instrument.   The GPIB interface has not been tested.

Database

The example database and EDM engineering screen provided as part of this support module prefix all record names with the macros “$(P)$(R)”.  Typically the $(P) macro would expand to a “per-IOC” string and the $(R) macro would expand to a string unique to each of the Keithley 6487 instruments connected to the IOC.

Several of the records have the characters 'RBV' at the end.   This indicates that they are the 'Read Back Value' corresponding to an output record with the same name minus the RBV.

IEEE-488.2 Records

Record
Name
 Record
Type
 Description
$(P)$(R)IDN waveform
 Instrument identification string (FTVL=CHAR).  A waveform record must be used since the identification string is too long to fit into a stringin record.
$(P)$(R)RST
 bo
 Reset all settings to default values.
$(P)$(R)CLS
 bo
 Clear error message queue and all event register bits.
$(P)$(R)GetSTB
 longin
 Read system status byte register.
$(P)$(R)GetESR
 longin
 Read and clear the system event status register.
$(P)$(R)GetESE
$(P)$($)SetESE
 longin
longout
 Read/Write the system event status enable register.
$(P)$(R)GetSRE
$(P)$($)SetSRE		 longin
longout		 Read/Write the system service request enable register.
$(P)$(R)TRG
 bo
 Send a bus trigger to the instrument.
$(P)$(R)GetOPC
 bi
 Read the operation complete status.

The TRG and GetOPC record are not that useful since the 6487 does not process commands when in triggered acquisition mode.  For example, the operation complete status simply waits till the 6587 has acquired the full set of triggered samples and then reads back as 1.  Any other command (e.g. FETCH?) would have the same effect of waiting until the end of triggered acquisition and then returning.

Range Selection Records

Record
Name
 Record
Type
 Description
$(P)$(R)Range
$(P)$(R)RangeRBV
 mbbo
mbbi
 Set/get the full-scale range of the instrument (2 nA to 20 mA).
$(P)$(R)AutoRange
$(P)$(R)AutoRangeRBV
 bo
bi
 Set/get the status of the instrument auto-range operation.  A search of every available range is performed every time an autorange occurs.  This can significantly slow down data acquisition.

Measurement Records

Record
Name
 Record
Type
 Description
$(P)$(R)Measure ai
 Send a ‘MEASure?’ command to measure and return the value of the current.
Note that this operation changes the settings of several triggering parameters.  To return to triggered operation process the $(P)$(R)RestoreTriggerSettings record.
$(P)$(R)FetchWF
 waveform
 Read back the samples acquired during the most recent triggered acquisition session.  This command does not trigger a measurement.  It simply requests the last group of readings.

Filtering Records

Record
Name
 Record
Type
 Description
$(P)$(R)IntegrationTime
$(P)$(R)IntegrationTimeRBV
 ao
ai
 The time (in units of power-line cycles) to sample data for a single measurement.
$(P)$(R)Damping
$(P)$(R)DampingRBV
 bo
bi
 The status of the instrument damping.  Damping helps reduce the noise resulting from large source or cable capacitance but slows down acquisition.
$(P)$(R)FilterEnable
$(P)$(R)FilterEnableRBV
 bo
bi
 The status of the instrument digital boxcar filter.
$(P)$(R)FilterCount
$(P)$(R)FilterCountRBV
 longout
longin
 The number of samples (2 to 60) in the instrument boxcar filter.

Triggered Acquisition Records

These affect triggered acquisition only.   The MEASure? command overrides these settings.

Record
Name
 Record
Type
 Description
$(P)$(R)ArmSource
$(P)$(R)ArmSourceRBV
 mbbo
mbbi
 The source which will arm the instrument when in triggered acquisition mode.
$(P)$(R)ArmTimerInterval
$(P)$(R)ArmTimerIntervalRBV
 ao
ai
 The time (seconds) between arm operations when arm source is ‘Timer’.
$(P)$(R)ArmLine
$(P)$(R)ArmLineRBV
 mbbo
mbbi
 The trigger link line (1 through 6) to be used  when arm source is ‘Trigger Link’.
$(P)$(R)ArmCount
$(P)$(R)ArmCountRBV
 longout
longin
 The number of arm operations in a completed triggered acquisition sequence.
 $(P)$(R)TriggerSource
$(P)$(R)TriggerSourceRBV		 mbbo
mbbi		 The source which will trigger the instrument when in triggered acquisition mode and armed.
$(P)$(R)TriggerLine
$(P)$(R)TriggerLineRBV
 mbbo
mbbi		 The trigger link line (1 through 6) to be used  when trigger source is ‘Trigger Link’.
$(P)$(R)TriggerDelay
$(P)$(R)TriggerDelayRBV		 ao
ai		 Delay (seconds) from trigger to  data acquisition.
$(P)$(R)TriggerDelayAuto
$(P)$(R)TriggerDelayAutoRBV		 bo
bi
 Set trigger delay based on range or used fixed ($(P)$(R)TriggerDelay) value.
$(P)$(R)TriggerCount
$(P)$(R)TriggerCountRBV		 longout
longin		 The number of trigger operations in a single arm cycle of a triggered acquisition sequence.
$(P)$(R)Start bo
 When this record is processed a triggered acquisition sequence will be initiated.  No other commands will complete until the sequence has finished or been canceled.
$(P)$(R)Cancel bo
 When this record is processed a triggered acquisition sequence will be canceled.
$(P)$(R)RestoreTriggerSettings seq
 Process all the triggering control records to write the settings back to the instrument.  This is necessary when switching from ‘MEASure?’ to triggered acquisition.
$(P)$(R)ReadTriggerSettings seq
 Process all the triggering control readback records.

Local Controls Records

Record
Name
 Record
Type
 Description
$(P)$(R)KLOCK
$(P)$(R)KLOCKRBV
 bo
bi
 Lock out the instrument front-panel controls.  When set all front-panel controls, including the LOCAL button, are disabled.

Voltage Source Records

Record
Name
 Record
Type
 Description
$(P)$(R)SourceEnable
$(P)$(R)SourceEnableRBV
 bo
bi
 Voltage source off/on.
$(P)$(R)SourceInterlock
$(P)$(R)SourceInterlockRBV
 bo
bi
 Disable/enable external interlock when in 10V range.  The external interlock is always enabled in the 50V and 500V ranges.  The readback value is 1 when the interlock is enabled and the external interlock chain is open.
$(P)$(R)SourceRange
$(P)$(R)SourceRangeRBV
 mbbo
mbbi
 Voltage source range (10V, 50V, 500V).
$(P)$(R)SourceIlimit
$(P)$(R)SourceIlimitRBV
 mbbo
mbbi
 Current limit (25 uA, 250 uA, 2.5 mA, 25 mA).  The 25 mA limit is available only when the source is in the 10V range.
$(P)$(R)SourceVoltage
$(P)$(R)SourceVoltageRBV		 ao
ai		 Voltage source setpoint and setpoint readback.  The setpoint must be resent after an interlock fault.  Turning the source off/on is not sufficient.
$(P)$(R)SourceReadSettings seq
 Process all the voltage source readback records.


Installation and Building

After obtaining a copy of the distribution, it must be installed and built for use at your site.
  1. Create an installation directory for the module. The path name of this directory should end with modules/instrument/keithley6487.
  2. Place the distribution file into this directory.
  3. Execute the following commands:
    cd modules/instrument/keithley6487
    gunzip keithley6487<release>.tar.gz
    tar xvf keithley6487<release>.tar
    cd <release>
    Where <release> is the release number of of the Keithley6487 support.
  4. Edit the configure/RELEASE file and set the paths to your installation of EPICS base, stream and ASYN support modules.
  5. Execute make in the top level directory.