Release Notes

ECMC 8.0.0

Add support for jerk limited trajectories based on ruckig (https://github.com/pantor/ruckig). Trapetzoidal trajectories still supported and default in ecmccfg. Ruckig module is now a dependency.

Note S-curve trajectory restrictions: On the fly velocity target changes not allowed when posiitoning (blocked).
Update of trajectory generator to allow "on the fly" update of target postion and target velocity (trapetz).
Ensure that master is not scanning slaves at startup. If scanning then wait until scan is finished (with timeout).
Remove commands Cfg.SetOpMode() and GetOpMode(). Obsolete and not used.
Add command "Cfg.SetAxisHomePosition()", same as Main.Mx.fHomePosition (try to phase out this old syntax)
Add possibility to run motion without motor record.

Control params:

ax<id>.control
ax<id>.command
ax<id>.cmddata
ax<id>.targpos
ax<id>.targvelo

Status params:

ax<id>.status
ax<id>.actpos
ax<id>.setpos
ax<id>.poserr
ax<id>.diagnostic

Examples and more info are available in: ecmccfg/examples/test/motionWithoutMotorRecord/

Brake handling:
- Engage brake if not enabled
- Start counting open delay when drive enabled goes high (instead of enable cmd).
Reset axis enable cmd if ethercat in error state (prevent re-enable when ethercat returns to OK)
Add command to set drive timeout for enabled and DS402 state machine: "Cfg.SetAxisDrvStateMachineTimeout(int axis_no, int seconds)"
Fix of absolute encoder reading at ioc startup

ECMC 7.0.1

Add homing seq 25 (same as 15 but not blocked by motor record and reserved for save/restore). The sequence will just set a new position.
Add axisType in status word
Fix moving bit in motor record poll

ECMC 7.0.0

New release to match ecmccfg 7.0.0

Add functionality to move to a position after success full homing procedure. The functionality is configuerd by the follwing two commands:

1. ecmcConfigOrDie "Cfg.SetAxisHomePostMoveEnable(<axis_id>, <enable>)"                 # default disabled
2. ecmcConfigOrDie "Cfg.SetAxisHomePostMoveTargetPosition(<axis_id>,<target position>)" # default 0.0

Add homing seq 7..10:
- seq 7 : Ref at first rising edge of home sensor moving in backward direction.
- seq 8 : Ref at first rising edge of home sensor moving in forward direction.
- seq 9 : Ref at center of home sensor rising edges:
  1. Move backward
  2. latch encoder position at rising edge of homesensor
  3. continue move backward until falling edge of homsensor, then stop
  4. Move forward and latch encoder position at rising edge of home sensor, then stop
  5. Reference at centerpoint between the two latched positions to homeposition value.
- seq 10: Ref at center of home sensor rising edges:
  1. Move forward
  2. latch encoder position at rising edge of homesensor
  3. continue move forward until falling edge of homsensor, then stop
  4. Move backward and latch encoder position at rising edge of home sensor, then stop
  5. Reference at centerpoint between the two latched positions to homeposition value.
Note: Polarity of home sensor can be changed with the following command:
```
"Cfg.SetAxisMonHomeSwitchPolarity(int axisIndex, int polarity)";
# polarity==0 is NC (default)
# polarity==1 is NO
```

Migration guide (6.x.x to 7.0.0)

Version 7 of ecmc and ecmccfg is intended to be more flexible in PV naming making it possible to follow for instance the ESS naming standard. At the same time a more systematic/genric approach to naming have been implemneted making use of macros easier. Because of these changes v7 is not compatible with v6. The last version of ecmc and ecmccfg with the old naming is v6.3.3.

What have changed

The changes are described in detail in this file: Naming Convention

These changes will mainly affect:

Default ecmc PV names
ecmc parameter names

1. PV names

Updated PV names affects:

Local databases accesing data from ecmc PV:s
OPIs accessing data from ecmc PVs
Archiving configuration

Example of updated PV name:

Old:
IOC_TEST:ec0-s6-EL5101-Enc-PosAct

New:
IOC_TEST:m0s006-Enc01-PosAct

2. ecmc parameter names

Updated ecmc paramter names affects:

Local databases accesing data directlly from ecmc parameters
EtherCAT variables in ecmc PLC:s
Motion configuration links to hardware (in both normal *.ax files and sync files. *.sax)

Example of updated ecmc parameter name:

Old:
ec0.s5.BI_7

New:
ec0.s5.binaryInput07

Example of needed update in PLC code and sync files:

Old:
ec0.s5.BO_7:=ec0.s1.CH1_VALUE > 500;

New:
ec0.s5.binaryOutput07:=ec0.s1.analogInput01 > 500;

Example of needed update of hardware links in motion configuration file:

Old:
epicsEnvSet("ECMC_EC_DRV_CONTROL",        "ec0.s8.STM_CONTROL.0")        # Ethercat entry for control 

New:
epicsEnvSet("ECMC_EC_DRV_CONTROL",        "ec0.s8.driveControl01.0")     # Ethercat entry for control

New Functionalities 6.3.3

Also update the motion copnfiguration files with the new functionalities in ecmc 6.3.3.

Drive and Encoder Alarms, Warning and reset linked to motor record

Since ecmc 6.3.3 the follwing can be linked to the motion axis:

3 drive hardware alarms
1 drive reset error bit
1 drive warning bit
3 encoder hardware alarms
1 encoder reset error bit
1 encoder warning bit

Alarms:

If any of the alarm bits is going high the axis will stop and and an alarm meassage will be propagated to motor record (if used).

Reset:

The reset bit is linked to the motor record reset PV (a reset from motor reset pv will result in reset toggle for 1 scan).

Warning:

The warning bit will at the moment just result in a printout in the iocsh log. Several drives, like el7037, are in warning state when not enabled.

Variables:

In order to use the new alarm and reset functionality some new varaibles need to be set in the motion configuration files.

Example EL7037 and EL5002:

# Add to drive section (example of EL7037 drive):
epicsEnvSet("ECMC_EC_DRV_RESET",          "ec0.s8.driveControl01.1")      # Reset
epicsEnvSet("ECMC_EC_DRV_ALARM_0",        "ec0.s8.driveStatus01.3")       # Error
epicsEnvSet("ECMC_EC_DRV_ALARM_1",        "ec0.s8.driveStatus01.7")       # Stall
epicsEnvSet("ECMC_EC_DRV_ALARM_2",        "ec0.s8.driveStatus01.14")      # Sync error
epicsEnvSet("ECMC_EC_DRV_WARNING",        "ec0.s8.driveStatus01.2")       

# Add to encoder section (example of EWL5002 SSI encoder):
epicsEnvSet("ECMC_EC_ENC_RESET",          "")                             # Reset (no reset bit)
epicsEnvSet("ECMC_EC_ENC_ALARM_0",        "ec0.s3.encoderStatus01.0")     # Error 0: SSI input error
epicsEnvSet("ECMC_EC_ENC_ALARM_1",        "ec0.s3.encoderStatus01.1")     # Error 1: SSI frame error
epicsEnvSet("ECMC_EC_ENC_ALARM_2",        "ec0.s3.encoderStatus01.2")     # Error 2: Encoder power fail
epicsEnvSet("ECMC_EC_ENC_WARNING",        "")                             # Warning (no warning bit)

Note: that the above examples are for EL7037 and EL5002. For other drives and encoders other hardware links need to be added.

The bits can be linked to any ethercat entries.

ECMC 6.3.3

Block setEnable from motor record if ax.blockcom==1
Block mc_* plc functions if ax.allowplccmd==0
Allow plc:s to write to axis as default.
Increase max allowed datastorage count to 32
Increase max allowed plc count to 16
Add alarm and reset links to axis encoder and drive object (that can be assigned with the "Cfg.LinkEcEntryToObject()"-command):
- ax.enc.reset
- ax.enc.alarm0
- ax.enc.alarm1
- ax.enc.alarm2
- ax.enc.warning
- ax.drv.reset
- ax.drv.alarm0
- ax.drv.alarm1
- ax.drv.alarm2
- ax.drv.warning
The intention with these links is to link drive and encoder related errors and reset commads to interlock motion and display alarms in axis error field. For an EL7037 the following bits could be mapped:
- ax.drv.reset to ec.s.STM_CONTROL.1 // Reset bit in drive control word.
- ax.drv.alarm0 to ec.s.STM_STATUS.3 // Error bit in drive status word.
- ax.drv.alarm1 to ec.s.STM_STATUS.7 // Stall bit drive status word.
- ax.drv.alarm2 to ec.s.STM_STATUS.14 // Sync error bit drive status word.
- ax.drv.warning to ec.s.STM_STATUS.2 // Warning bit drive status word.
If the reset link is defined then this bit will be set for one cycle when issueing an error reset command. Note: Any of these new links can be left unused/blank.
Add plc function mc_home_pos(): Reference encoder to a postion (same as mc_home but with an extra argument for position, so no need to set home position with ax.enc.homepos).
Add plc function mc_move_ext_pos(): Plc function will move axis to the current external plc setpoint. Inteded to be used to move a slave axis to it's start position before allowing external setpoints.
Add variables:
- ax.enc.extactpos (ro): Current external plc calculated actual position (ax.enc.actpos can be used for writing).
- ax.traj.extsetpos (ro): Current external plc calculated setpoint position(ax.enc.setpos can be used for writing).
Position setpoint is syncronized with actual position when axis is disabled. Setpoint is updated once at positive edge of enable command. Note: The position setpoint is synced with actual position before first enable.

ECMC 6.3.2

Add command to enable/disable motion functions (all are by default enabled):

ecmcConfigOrDie "Cfg.SetAxisEnableMotionFunctions(<axisid>,
                                                  <enable pos>,
                                                  <enable const velo>,
                                                  <enable home>)"

ecmc-updated param changed to uint64 if asyn version >=4.37
Fix printout of plugin plc functions info for funcs with more than 6 args.

ECMC 6.3.1

Add support for 64 bit integers (if ASYN version >= 4.37)
Add plc function to push memmaps to epics on demand (used when T_SMP_MS=-1):
```
ec_mm_push_asyn(<memmap id>)
```

Add command to get memmap id from name: EcGetMemMapId(). Can be used to feed memmap ids into PLCs.

ecmcConfig "EcGetMemMapId(ec0.s11.mm.CH1_ARRAY_IN)"
epicsEnvSet(MM_CH_1_IN,${ECMC_CONFIG_RETURN_VAL})

Add command to use CLOCK_REALTIME (instead of CLOCK_MONOTONIC which is default in ecmc):

Use CLOCK_REALTIME:
ecmcConfigOrDie "Cfg.EcUseClockRealtime(1)"
Use CLOCK_MONOTONIC:
ecmcConfigOrDie "Cfg.EcUseClockRealtime(0)"

Allow up to 64 memmaps (before max 16)
Add command to diable axis at reset:

Cfg.SetAxisDisableAtErrorReset(<axis id>, disable)

ECMC 6.3.0

Add axis control word and update axis status word (phasing out stream)
Add ethercat summary status bit (asyn param ec.ok). Forced update each cycle.
Update domain status each cycle
Use new motor record release (dependency on motor 7.0.4)
Support for motor record RDBL
Bug fix in relative motion (when using RDBL)

ECMC 6.2.4

Add support for drive CSP mode (Cyclic Sync. Position interface). CSP can be used by linking a ethercat entry to "ax.drv.position" (and not linking an entry to "ax1.drv.velocity"):

# Setup CSP on axis 1:
ecmcConfigOrDie "Cfg.LinkEcEntryToObject(ec1.s3.SET_POSITION,"ax1.drv.position")"
ecmcConfigOrDie "Cfg.LinkEcEntryToObject("","ax1.drv.velocity")"

NOTE: The ecmc position control loop parameters will not have any effect in CSP mode (since position loop is distributed to the drive). Control parameters need to be set directlly in the drive (by SDO):

# These commands will not have any effect in CSP mode (set to 0, or you will get a warning meassage):
ecmcConfigOrDie "Cfg.SetAxisCntrlKp(${ECMC_AXIS_NO},${ECMC_CNTRL_KP})"
ecmcConfigOrDie "Cfg.SetAxisCntrlKi(${ECMC_AXIS_NO},${ECMC_CNTRL_KI})"
ecmcConfigOrDie "Cfg.SetAxisCntrlKd(${ECMC_AXIS_NO},${ECMC_CNTRL_KD})"
ecmcConfigOrDie "Cfg.SetAxisCntrlKff(${ECMC_AXIS_NO},${ECMC_CNTRL_KFF})"
...

Update to DS402 timeout unit to seconds (before it was cycles).
Add possabilty to verify actual ec slave revision vs config revsion with "Cfg.EcSlaveVerify()" command. The slave revision number must be higher or equal (>=) comapred to the config revsion number in order to be approved. Note: Comparsion is only made if the supplied config revsion number >= 0. Note: "Cfg.EcSlaveVerify()" can still be used without revsion number and then the revsion chesk will not be performed.
Add encoder position averaging lp-filter:
- Cfg.SetAxisEncPosFilterSize(<axis_id>,<filter_size>)
- Cfg.SetAxisEncPosFilterEnable(<axis_id>,)
Plugin interface: Fix sampeltime unit to ms
Add warnings for 64bit ethercat plc variables (might not be represented properly since all plc variables are doubles). A typical example would be a 64bit dc-timestamp.
Add plc- functions
- ds_append_to_ds()
- ec_mm_append_ds()
Minor fix of float and double ec entries
Minor fix asynUint32Digital interface

ECMC 6.2.3

Add support for motor auto enable/disable
Add plc functions ec_get_time_u32(), ec_get_time_l32().
ecmcForLoop: iocsh command: Support decreasing iterations
Fix moving bit in ecmcMotorRecordAxis::poll()

ECMC 6.2.2

Allow JVEL change while jogging
Smoother trajectory at stopping (start stop seq. one cycle earlier than before to avoid small jerk at stop)
Update to support autosave of motor position

ECMC 6.2.1

Add exprtk support for plc functions with stings as args (need ess-exprtk 1.2.1)
Add possabilty ti use plc-functions with strings a sarguments in plugins
Expose ecmc epics ioc state to plugins
Add plugin for pvAccess in ecmc plc:s: https://github.com/anderssandstrom/e3-ecmcPlugin_Utils

ECMC 6.2

Add plugin support

ecmc plugins (shared libs) can be loaded into ecmc. Plugins can:

Access ecmc data:
- ethercat data
- motion data
- plc data
- data storages
- subscribe to data by callbacks
- Add/register new asyn parameters for direct access over asyn
Get callbacks:
- Each realtime loop
- When ecmc data updates
- At plugin load
- At plugin unload
- At enter realtime
- At exit realtine
Implement custom ecmc plc functions
Implement custom ecmc plc constants

A plugin can also access the ecmc api headers for direct access to most parts of ecmc.

Some plugin examples:

FFT plugin: https://github.com/anderssandstrom/e3-ecmcPlugin_FFT
Demo plugin: https://github.com/anderssandstrom/e3-ecmcPlugin_Advanced
WiringPi ecmc wrapper: https://github.com/anderssandstrom/e3-ecmcPlugin_RasPi

Plugins can be loaded by the ecmccfg command loadPlugin.cmd. Plugin configurations can be added in a configurations string. Example:

#- Load plugin 0: Advanced
epicsEnvSet(ECMC_PLUGIN_FILNAME,"/epics/base-7.0.3.1/require/3.1.2/siteMods/ecmcPlugin_Advanced/master/lib/linux-arm/libecmcPlugin_Advanced.so")
epicsEnvSet(ECMC_PLUGIN_CONFIG,"DBG_PRINT=0;") # Only one option implemented in this plugin
${SCRIPTEXEC} ${ecmccfg_DIR}loadPlugin.cmd, "PLUGIN_ID=0,FILE=${ECMC_PLUGIN_FILNAME},CONFIG='${ECMC_PLUGIN_CONFIG}', REPORT=1"
epicsEnvUnset(ECMC_PLUGIN_FILNAME)
epicsEnvUnset(ECMC_PLUGIN_CONFIG)

Allow running without EtherCAT hardware

Add possibility to run without attached ethercat hardware. Most functionalities are still available:

PLC:s
motion (most likely to use virtual axes, but also normal axis can be used).
..

See examples in ecmccfg.

Note: When running without ethercat hardware you should not execute the "Cfg.EcSetMaster()" command.

Add iocsh command to exit

Add ecmcExit() to exit EPICS/ECMC (needed since the iocsh command "exit" just stops reading current "file"). Can be used for stopping execution when a configuration error occurs.

  Use "ecmcExit" to exit ecmc/EPICS.
  Use "ecmcExit -h | --help" to get help message.

Add iocsh command to execute for loop

Usefull for:

Large systems with many similar sub systems
Configuring hardware with many PDOs (oversampling)

"ecmcForLoop(<filename>, <macros>, <loopvar>, <from>, <to>, <step>)" to loop execution of file with a changing loop variable.
             <filename> : Filename to execute in for loop.
             <macros>   : Macros to feed to execution of file.
             <loopvar   : Environment variable to use as index in for loop.
             <from>     : <loopvar> start value.
             <to>       : <loopvar> end value.
             <step>     : Step to increase <loopvar> each loop cycle.

Example ("ECMC_LOOP_IDX" as loop variable):

ecmcForLoop(./loopStep.cmd,"",ECMC_LOOP_IDX,1,5,1)
ecmcEpicsEnvSetCalc("TESTING",1*10)
epicsEnvShow("TESTING")
TESTING=10
ecmcEpicsEnvSetCalc("TESTING",2*10)
epicsEnvShow("TESTING")
TESTING=20
ecmcEpicsEnvSetCalc("TESTING",3*10)
epicsEnvShow("TESTING")
TESTING=30
ecmcEpicsEnvSetCalc("TESTING",4*10)
epicsEnvShow("TESTING")
TESTING=40
ecmcEpicsEnvSetCalc("TESTING",5*10)
epicsEnvShow("TESTING")
TESTING=50

where "loopStep.cmd" file looks like this (note the use of "ECMC_LOOP_IDX"):

#- Commands tp execute in each loop of example ecmcForLoop.script
ecmcEpicsEnvSetCalc("TESTING",${ECMC_LOOP_IDX}*10)
epicsEnvShow("TESTING")

Add iocsh command to check if a file exist

Usefull for checking that configuration files really exist and then can be loaded.

ecmcFileExist(<filename>, <die>, <check EPICS dirs>, <dirs>)" to check if a file exists.
              <filename>          : Filename to check.
              <die>               : Exit EPICS if file not exist. Optional, defaults to 0.
              <check EPICS dirs>  : Look for files in EPICS_DB_INCLUDE_PATH dirs. Optional, defaults to 0.\n");
              <dirs>              : List of dirs to search for file in (separated with ':').
result will be stored in the EPICS environment variable "ECMC_FILE_EXIST_RETURN_VAL"

Example:

ecmcFileExist("file_exist.cfg")
epicsEnvShow(ECMC_FILE_EXIST_RETURN_VAL)
ECMC_FILE_EXIST_RETURN_VAL=1

ecmcFileExist("file_not_exist.cfg",1)
Error: File "file_not_exist.cfg" does not exist. ECMC shuts down.

ecmcFileExist("ecmcEK1100.substitutions",1,1)
epicsEnvShow(ECMC_FILE_EXIST_RETURN_VAL)
ECMC_FILE_EXIST_RETURN_VAL=1

ecmcFileExist("ecmcEK1100.substitutions",0,0,"/home/")
epicsEnvShow(ECMC_FILE_EXIST_RETURN_VAL)
ECMC_FILE_EXIST_RETURN_VAL=0

Add new commands to set sample rate:

Preferred way. Write to the parameter "EC_RATE" of startup.cmd (unit of EC_RATE is [Hz]):

$(ECMCCFG_INIT)$(SCRIPTEXEC) ${ecmccfg_DIR}startup.cmd, "IOC=$(IOC),ECMC_VER=<ecmcVersion>,stream_VER=<stremVer>, EC_RATE=<rate>"

Issueing the command "ecmcConfigOrDie "Cfg.SetSampleRate()" where the unit of sampleRate is [Hz]:

ecmcConfigOrDie "Cfg.SetSampleRate(500)"

Issueing the command "ecmcConfigOrDie "Cfg.SetSampleTimeMs()" where unit of sampleTime is [ms]:

ecmcConfigOrDie "Cfg.SetSampleTimeMs(2)"

Note: The commands "Cfg.SetSampleRate()" or "Cfg.SetSampleTimeMs()" needs to be executed before any ecmc configuration is performed but of cource after the "require ecmc" statement. Therefore the parameter EC_RATE is the prefereed way to handle changed sample rates.

Example and doc in: ecmccfg/examples/test/changeSampleRate/

ecmcConfig(OrDie) result to epics environment variable

The return value from ecmcConfig(OrDie) is stored in the EPICS environment variable "ECMC_CONFIG_RETURN_VAL". This value can be used to make som dynamic configuration. All ASCII configuration commands for ecmcConfig(OrDie) can be used in the same way.

Example: Read firmware version of an EL7037 stepper drive Note: SDO reads need to be before "SetAppMode(1)"

ecmcConfig "EcReadSdo(${ECMC_SLAVE_NUM},0x100a,0x0,2)"
epicsEnvShow(ECMC_CONFIG_RETURN_VAL)
ECMC_CONFIG_RETURN_VAL=14640

The variable "ECMC_CONFIG_RETURN_VAL" then can be used to set record fields, name or alias for instance..

Example: Read "ID" PDO from EK1101 (shown in detail in aliasRecordFromPdoData.script) Note: PDO reads need to be after "SetAppMode(1)" since cyclic value

ecmcConfig "ReadEcEntryIDString(${ECMC_SLAVE_NUM},"ID")"
2020/02/28 08:58:03.771 1024
## This is the value of the EK1101 ID switch
epicsEnvShow(ECMC_CONFIG_RETURN_VAL)
ECMC_CONFIG_RETURN_VAL=1024

Add "ecmcEpicsEnvSetCalcTernary()"

Used for evaluating expressions and set EPCIS environment variables to different strings. depending on if the expression evaluates to "true" or "false". Can be usefull for:

Choose different files to load like plc-files, axis configurations, db-files or..
making conditional ecmc settings
...

ecmcEpicsEnvSetCalcTernary -h

 Test iocsh function "ecmcEpicsEnvSetCalcTernary()" t

        Use "ecmcEpicsEnvSetCalcTernary(<envVarName>,  <expression>, <trueString>, <falseString>)" to evaluate the expression and        assign the variable.
          <envVarName>  : EPICS environment variable name.
          <expression>  : Calculation expression (see exprTK for available functionality). Examples:
                          Simple expression:"5.5+${TEST_SCALE}*sin(${TEST_ANGLE}/10)".                          
                          Use of "RESULT" variable: "if(${TEST_VAL}>5){RESULT:=100;}else{RESULT:=200;};".
                          Strings are used within '<str>': "'test'='test'". Note: expression result must be numeric and 
                          not string (in this case expression result is 1 => <envVarName> will be set to <trueString>).
          <trueString>  : String to set <envVarName> if expression (or "RESULT") evaluates to true.
          <falseString> : String to set <envVarName> if expression (or "RESULT") evaluates to false.

Examples:

#### Simple true false
epicsEnvSet("VALUE",10)
# ecmcEpicsEnvSetCalcTernary("test_var", "${VALUE}+2+5/10","True","False")
ecmcEpicsEnvSetCalcTernary("test_var", "10+2+5/10","True","False")
epicsEnvShow("test_var")
test_var=True

### Can be used for choosing different files
# ecmcEpicsEnvSetCalcTernary("filename", "${VALUE}>20","./plc_fast.cfg","./plc_slow.cfg")
ecmcEpicsEnvSetCalcTernary("filename", "10>20","./plc_fast.cfg","./plc_slow.cfg")
epicsEnvShow("filename")
filename=./plc_slow.cfg

### Comparing strings 1 (simple):
# ecmcEpicsEnvSetCalcTernary("result", "'$(filename)'='./plc_slow.cfg'","equal","not_equal")
ecmcEpicsEnvSetCalcTernary("result", "'./plc_slow.cfg'='./plc_slow.cfg'","equal","not_equal")
epicsEnvShow("result")
result=equal

### Comparing strings 2 (with if-else):
# ecmcEpicsEnvSetCalcTernary("result", "if('$(filename)'='test') {RESULT:=1;}else{RESULT:=0;};","use_this_file.cfg","no_use_this_file.cfg")
ecmcEpicsEnvSetCalcTernary("result", "if('./plc_slow.cfg'='test') {RESULT:=1;}else{RESULT:=0;};","use_this_file.cfg","no_use_this_file.cfg")
epicsEnvShow("result")
result=no_use_this_file.cfg

Add "ecmcEpicsEnvSetCalc()"

iocsh command for evaluating expressions and setting epics environment variables. Usefull for calculate:

slave offsets
sdo/pdo adresses (also in hex)
scalings in motion
record fields
...

ecmcEpicsEnvSetCalc -h

      "ecmcEpicsEnvSetCalc(<envVarName>,  <expression>, <format>)"
          <envVarName> : EPICS environment variable name.
          <expression> : Calculation expression (see exprTK for available functionality).
                         Simple expression:"5.5+${TEST_SCALE}*sin(${TEST_ANGLE}/10)".                          
                         Use of "RESULT" variable: "if(${TEST_VAL}>5){RESULT:=100;}else{RESULT:=200;};".
                         Strings are used within '<str>': "'test'='test'". Note: expression result must be numeric and 
                         not string (in this case expression result is 1 => <envVarName> will be set to "1").
          <format>     : Optional format string. Example "%lf", "%8.3lf", "%x", "%04d" or "%d", defaults to "%d".
                         Can contain text like "0x%x" or "Hex value is 0x60%x".
                         Must contain one numeric value where result of expression will be written.

       Restrictions:
         - Some flags and/or width/precision combinations might not be supported.
         - Hex numbers in the expression is not allowed (but hex as output by formating is OK).
         - Non floatingpoint values will be rounded to nearest int.