Dependencies of EPICS PVs on MX record fields, etc.

                         Last updated January 23, 2012


This document describes how EPICS PVs created by the MX-based Channel Access
server depend on the underlying MX record fields as well as other
dependencies.

All records:

  DESC - "label"

  NAME - "name"


Motor Record:

  ACCL - "acceleration_time"

  ACOF - "acceleration_feedforward_gain"

  ATHM - Created by mxcaMotorMstaPV().  See MSTA description.

  BACC - "acceleration_time"

  BDST - "backlash_correction"

  BVEL - "speed"

  CARD - Dummy short PV.  Initialized to -1.

  DCOF - "derivative_gain"

  DHLM - Created by mxcaMotorDialPV( ..., "positive_limit" )
           Read:
              DHLM = "positive_limit"
              HLM = DHLM * DIR + OFF

  DIFF - Created by mxcaMotorDiffPV().
           Read:
              DIFF = VAL - RBV

  DIR  - Internal enum PV created by mxcaMotorDirPV().
           Write:
              VAL = OFF + DIR * DVAL
              HLM = OFF + DIR * DHLM
              LLM = OFF + DIR * DLLM
              RBV = OFF + DIR * DRBV

  DLLM - Created by mxcaMotorDialPV( ..., "negative_limit" )
           Read:
              DLLM = "negative_limit"
              LLM = DLLM * DIR + OFF

  DMOV - Created by mxcaMotorMstaPV().  See MSTA description.

  DRBV - Created by mxcaMotorDialPV( ..., "position" )
           Read:
              DRBV = "position"
              RBV = DRBV * DIR + OFF

  DTYP - Internal string PV.  Initialized to 'MxMotor'.

  DVAL - Created by mxcaMotorDvalPV().
           Read:
              Set VAL = DVAL * DIR + OFF

           Write:
              1.  Gets the value of DIR.
              2.  Checks to see if DVAL is outside the range of DHLM
                  and DLLM and sets LVIO accordingly.
              3.  If SET == 'Use',
                     If (SPMG == 'Go') and (LVIO == 0),
                        DMOV is set to 0.
                        If new_dval >= mx_motor->position,
                           Set TDIR to 1.
                        Else
                           Set TDIR to 0.
                        Endif
                        Force value change for MSTA.
                        Start the move by writing to "destination".
                     Endif
                     Set VAL = DVAL * DIR + OFF.

                  Else if SET == 'Set',
                     If (FOFF == 'Variable'),
                        Set OFF = VAL - DVAL * DIR.
                        Post value change for OFF.
                        Return
                     Endif
                     raw_set_position = (DVAL - OFF) / EGU
                     Write raw_set_position to "set_position".
                  Endif
              4.  Post value change for DVAL and VAL.

  EGU  - "units"

  ERES - "scale"

  FOFF - Internal enum PV: 'Variable', 'Frozen'.  Initialized to 'Variable'.

  HLM  - Created by mxcaMotorUserPV( ..., DHLM )
            Write:
               DHLM = DIR * ( HLM - OFF )

  HLS  - "positive_limit_hit"

  HOMF - Created by mxcaMotorHomePV( this, 'HOMF', 1 ).
           Write:
              If (HOMF == 1),
                 if (DMOV != 1),
                    mx_motor_soft_abort()          "soft_abort"
                    mx_wait_for_motor_stop()       "status"
                    Set DVAL = DRBV
                 Endif
                 Force value change for MSTA
                 mx_motor_find_home_position()     "home_search"
              Endif

  HOMR - Created by mxcaMotorHomePV( this, 'HOMR', -1 ).
           Write:
              If (HOMR == 1),
                 if (DMOV != 1),
                    mx_motor_soft_abort()          "soft_abort"
                    mx_wait_for_motor_stop()       "status"
                    Set DVAL = DRBV
                 Endif
                 Force value change for MSTA
                 mx_motor_find_home_position()     "home_search"
              Endif

  ICOF - "integral_gain"

  JOGF - Created by mxcaMotorJogPV( this, 'JOGF', 1 )
           Write:
              If (JOGF != 0),
                 if (DMOV != 1),
                    mx_motor_soft_abort()          "soft_abort"
                    mx_wait_for_motor_stop()       "status"
                    Set DVAL = DRBV
                 Endif
                 mx_motor_constant_velocity_move() "constant_velocity_move"
              Else if (JOGF == 0),
                 Capture position                  "position"
                 mx_motor_soft_abort()             "soft_abort"
                 mx_wait_for_motor_stop()          "status"
                 Move to captured position         "destination"
              Endif

  JOGR - Created by mxcaMotorJogPV( this, 'JOGR', -1 )
           Write:
              If (JOGR != 0),
                 if (DMOV != 1),
                    mx_motor_soft_abort()          "soft_abort"
                    mx_wait_for_motor_stop()       "status"
                    Set DVAL = DRBV
                 Endif
                 mx_motor_constant_velocity_move() "constant_velocity_move"
              Else if (JOGR == 0),
                 Capture position                  "position"
                 mx_motor_soft_abort()             "soft_abort"
                 mx_wait_for_motor_stop()          "status"
                 Move to captured position         "destination"
              Endif

  LLM  - Created by mxcaMotorUserPV( ..., DLLM )
            Write:
               DLLM = DIR * ( LLM - OFF )

  LLS  - "negative_limit_hit"

  LVIO - Internal short PV.  Initialized to 0.

  MISS - Internal short PV.  Initialized to 0.

  MOVN - Created by mxcaMotorMstaPV().  See MSTA description.

  MRES - "scale"

  MSTA - Created by mxcaMotorMstaPV().
           Read:
              Set values of ATHM, DMOV, MOVN, and MSTA
              based on the value reported by motor->status.    "status"

  OFF  - Created by mxcaMotorOffPV().
           Write:
              VAL = OFF + DIR * DVAL
              HLM = OFF + DIR * DHLM
              LLM = OFF + DIR * DLLM
              RBV = OFF + DIR * DRBV

  PCOF - "proportional_gain"

  RBV  - Created by mxcaMotorUserPV( ..., DRBV )
           Write:
              DRBV = DIR * ( RBV - OFF )

  RDBD - Dummy short PV.  Initialized to 0.

  REP  - Created by mxcaMotorRxpPV().
           Read:
              If ( (new RRBV - old RRBV) > "raw_move_deadband" ),
                 Report position in encoder units.
              Endif

  RLV  - Created by mxcaMotorRlvPV().
           Read:
              Does nothing.

           Write:
              Set VAL = VAL + RLV
              Set RLV = 0

  RMP  - Created by mxcaMotorRxpPV().
           Read:
              If ( (new RRBV - old RRBV) > "raw_move_deadband" ),
                 Report position in motor units.
              Endif

  RRBV - Created by mxcaMotorRrbvPV().
           Read or Write:
              DRBV = RRBV
              Post value changed for DRBV

  RVAL - "raw_destination"

  SET  - Internal enum PV: 'Use', 'Set'.  Initialized to 'Use'.

  SPMG - Created by mxcaMotorSpmgPV().
           Write:
              If (SPMG == 'Stop'),
                 mx_motor_soft_abort()       "soft_abort"
                 mx_wait_for_motor_stop()    "status"
              Else if (SPMG == 'Move'),
                 mx_motor_move_absolute()    "destination"

  STAT - Dummy short PV.  Initialized to 0.

  STOP - "soft_abort"

  TDIR - Internal short PV.  Initialized to 0

  TWF  - Created by mxcaMotorTweakPV( this, 'TWF', 1 ).
           Write:
              If (TWF == 1),
                 If (DMOV != 1),
                    mx_motor_soft_abort()          "soft_abort"
                    mx_wait_for_motor_stop()       "status"
                    Set DVAL = DRBV
                 Endif
                 VAL = VAL + TWF
                 Write to VAL
              Endif
              TWF = 0
              Post value changed for TWF.

  TWR  - Created by mxcaMotorTweakPV( this, 'TWR', -1 ).
           Write:
              If (TWR == 1),
                 If (DMOV != 1),
                    mx_motor_soft_abort()          "soft_abort"
                    mx_wait_for_motor_stop()       "status"
                    Set DVAL = DRBV
                 Endif
                 VAL = VAL + TWR
                 Write to VAL
              Endif
              TWR = 0
              Post value changed for TWR.

  TWV  - Internal double PV.  Initialized to 0.0.  Used by TWF and TWR.

  UEIP - Internal enum PV: 'No', 'Yes'.  Initialized to 'No'.

  VAL  - Created by mxcaMotorValPV().

  VBAS - "base_speed"

  VCOF - "velocity_feedforward_gain"

  VELO - "speed"

  VERS - Internal float PV.  Initialized to 6.3


Scaler Record:

  CNT  - Created by mxcaScalerCntPV().
           Read:
              Process gate record's "busy" field.

           Write:
              mx_timer_clear()
              Any needed from the following:
                 mx_analog_input_clear()
                 mx_digital_input_clear()
                 mx_scaler_clear()
                 mx_timer_clear()
              If gate channel is 1,
                 either mx_timer_stop() or mx_timer_start()
              Else
                 either mx_scaler_stop() or mx_scaler_start()
              Endif

  DLY  - Dummy float PV.  Initialized to 0.

  DTYP - Internal string PV.  Initialized to 'MxScaler'.

  EGU  - Internal string PV.  Initialized to 'sec'.

  FREQ - Created by mxcaScalerFreqPV().
           Write:
              T = S1 / FREQ
              TP = PR1 / FREQ

  G1   - Created by mxcaScalerGnPV().

  Gn   - Created by mxcaScalerGnPV().

  NM1  - Channel name from MX timer record's "name" field.

  NMn  - Channel name from MX scaler record's "name" field.

  PR1  - Created by mxcaScalerPr1PV().
           Write:
              TP = PR1 / FREQ

  PRn  - Created by mxcaScalerPrnPV().

  PREC - "precision"

  RATE - Dummy float PV.  Initialized to 0.

  S1   - Created by mxcaScalerS1PV().
           Read:
              Process timer "value" field.

  Sn   - Created by mxcaScalerSnPV().
           Read:
              Process record field:
                 analog input   "value"
                 digital input  "value"
                 motor          "position"
                 relay          "relay_status"
                 scaler         "value"
                 timer          "value"

  T    - Created by mxcaScalerTPV().

  Tp   - Created by mxcaScalerTpPV().
            Write:
               PR1 = TP * FREQ

  VERS - Internal float PV.  Initialized to 3.2