motorDSM/README.md

motorDSM

EPICS motor drivers for the following Dynamic Structures and Materials motor controllers: MD-90

motorDSM is a submodule of motor. When motorDSM is built in the motor/modules directory, no manual configuration is needed.

motorDSM can also be built outside of motor by copying it's configure/EXAMPLE_RELEASE.local file to RELEASE.local and defining the paths to EPICS_BASE, MOTOR, and itself.

motorDSM contains an example IOC that is built if configure/CONFIG_SITE.local sets BUILD_IOCS = YES. The example IOC can be built outside of the driver module. Copy iocs/dsmIOC/configure/EXAMPLE_RELEASE.local to RELEASE.local and uncomment and set the paths for the appropriate lines depending on whether motorDSM was built inside the motor module or independently.

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Compiling motorDSM

To set up a full EPICS stack for development and testing, install and configure all of the following dependencies:

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epics-base

Install make, gcc, and perl packages if not already installed, then clone and build epics-base:

$ export SUPPORT=/path/to/install/directory
$ cd $SUPPORT
$ git clone git@github.com:epics-base/epics-base.git
$ cd epics-base
$ make distclean
$ make

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asyn

$ cd $SUPPORT
$ git clone git@github.com:epics-modules/asyn.git

You may need to install (on Arch Linux) rpcsvc-proto package to get rpcgen binary needed to make asyn.

In asyn/configure, create the file RELEASE.local with contents:
SUPPORT=/path/to/install/directory
EPICS_BASE=/path/to/epics-base

In asyn/configure, create CONFIG_SITE.local file with the line:
TIRPC=YES
if appropriate header files are in /usr/include/tirpc/rpc instead of /usr/include/rpc.

$ cd $SUPPORT/asyn
$ make clean
$ make

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seq

$ cd $SUPPORT
$ git clone git@github.com:ISISComputingGroup/EPICS-seq.git seq

Install the re2c package (Arch) if needed.

Create seq/configure/RELEASE.local and set path for EPICS_BASE. (Note this package seems to forget to git-ignore the .local file.)

Edit seq/configure/RELEASE to add the missing '-' before the include for ISIS_CONFIG on the next to last line. This seems to be a typo.

$ cd $SUPPORT/seq
$ make clean
$ make

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motor

$ cd $SUPPORT
$ git clone git@github.com:epics-modules/motor.git

Create motor/configure/RELEASE.local and set SUPPORT, ASYN, SNCSEQ, and EPICS_BASE to the appropriate paths.

$ cd $SUPPORT/motor
$ make distclean
$ make

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motorDSM (this package)

$ cd $SUPPORT
$ git clone git@github.com:Binary-Coalescence/motorDSM.git

In motorDSM/configure, copy EXAMPLE_RELEASE.local to RELEASE.local and set paths for EPICS_BASE, MOTOR, and MOTOR_DSM.

In motorDSM/configure, copy EXAMPLE_CONFIG_SITE.local to CONFIG_SITE.local and uncomment to set:
BUILD_IOCS = YES

In motorDSM/iocs/dsmIOC/configure, copy EXAMPLE_RELEASE.local to RELEASE.local. Comment out the "if built inside motor" lines, uncomment the "if built outside motor" lines, and set the path for MOTOR_DSM.

$ cd $SUPPORT/motorDSM
$ make distclean
$ make

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Configuring the IOC server

The following steps must be used in either st.cmd.md90 (for a single unit) or in st.cmd.md90.multiple (for multiple units). st.cmd.md90.multiple includes 8 motors predefined on /dev/ttyUSB0 through /dev/ttyUSB7. Comment out all motors you don't need.

1. Define a new serial port named "serial0" and set the location of the physical port
drvAsynSerialPortConfigure([serial name], [device location], 0, 0, 0)
e.g., drvAsynSerialPortConfigure("serial0", "/dev/ttyUSB0", 0, 0, 0)

2. Configure the port

• Baud = 115200
• Bits = 8
• Parity = none
• Stop bits = 1
• Input end of message: "\r"
• Output end of message: "\r"
• Trace IO mask: 2

asynSetOption([serial name], 0, "baud", "115200")
asynSetOption([serial name], 0, "bits", "8")
asynSetOption([serial name], 0, "parity", "none")
asynSetOption([serial name], 0, "stop", "1")
asynOctetSetInputEos("serial0", 0, "\r")
asynOctetSetOutputEos("serial0", 0, "\r")
asynSetTraceIOMask("serial0", 0, 2)

where [serial name] is the name you assigned in step 1, surrounded by double quotes.

3. Set initial parameters

• Power supply enabled (EPS command)
• Deadband = 10 nm (SDB 10 command)

asynOctetConnect("initConnection", [serial name], 0)
asynOctetWrite("initConnection", "EPS")
asynOctetWrite("initConnection", "SDB 10")
asynOctetDisconnect('initConnection')

4. Create MD90 Controller object
MD90CreateController([controller name], [serial name], 1, 100, 5000)
where [controller name] is the name of the motor to assign. Convention is to use "MD90n", starting with n=0.

5. Intialize the IOC
After the call to iocInit (still in the st.cmd.md90[.multiple] file), issue the following commands for each motor. The example below uses DSM:m0 but it should be run for each line described in motor.substitutions.md90 (or motor.substitutions.md90.multiple).

dbpf("DSM:m0.RTRY", "0")	#sets retries to 0; this is automatic on the MD90
dbpf("DSM:m0.TWV", "0.1")	#Tweak distance
dbpf("DSM:m0.VMAX", "1.0")	#Sets max velocity to 1 mm/s
dbpf("DSM:m0.HVEL", "1.0")	#Sets max velocity to 1 mm/s

6. Update the substitutions file
Save and close the st.cmd file you've been configuring, then open the motor substitutions file (motor.substitutions.md90[.multiple]). Ensure the values in the pattern block's PORT field match the names used in the std.cmd file. Note that, despite this field being called "Port", they use the names of the MD90 Controller object defined above (by default, MD900, MD901, etc. Do not use the direct serial port names (by default, serial0, serial1, etc.).

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Running the example IOC

To run the example IOC, build the packages listed below, then:

1. Follow the steps in "Configuring the system for attached controllers" below.

2. Set the "EPICS_CA_ADDR_LIST" environment variable to include the IP address of the server. If it's running on the same computer, you can use the loopback IP address.
   $ export EPICS_CA_ADDR_LIST='127.0.0.1'

3. In the iocs/dsmIOC/iocBoot/iocDsm directory, run
   $ ../../bin/linux-x86_64/dsm st.cmd.md90
   for one attached MD-90 controller, or
   $ ../../bin/linux-x86_64/dsm st.cmd.md90.multi
   for eight attached MD-90 controllers. Edit this file to use more than one unit; simply comment out the ones you don't need.

4. Test using the caget and caput arguments as described in the "Example usage" section below.

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Example usage

After building, run the example IOC described at the top of this section in one terminal window. Open another terminal window and navigate to [EPICS install directory]/epics-base/bin/linux-x86_64/ (or wherever you built EPICS base.
Use the commands caget and caput to read and set process variables, respectively.

For example, to get the current position, use:
$ ./caget DSM:m0.REP
This reads the REP variable, which is the "Raw Encoder Position". Additionally, change m0 to m1, m2, etc. to read the values from other motors when running more than one.

Homing the motor (must be done before you can issue position commands):
$ ./caput DSM:m0.HOMF 1 #Begins homing sequence in the forward direction
or
$ ./caput DSM:m0.HOMR 1 #Begins homing sequence in the reverse direction

Moving to a position target:
$ ./caput DSM:m0.VAL 2.345 #Moves to 2.345 mm

Setting a velocity target:
./caput DSM:m0.VELO 0.5 #Sets velocity target to 0.5 mm/s
(Note that velocity targets are appropriate only. They adjust the step rate of the motor and are not guaranteed to be exact.)

A note aboue velocity targets

The I-20 motor driven by the MD-90 is a closed loop "step and repeat" motor that takes full steps towards its position target until it is close, then will perform linear extensions to close the loop on the target position. This is handled internally on the MD-90, not by EPICS.

The Velocity target parameter sets the step frequency at which the motor operates on its way to the target position. The speed is not closed loop, and will depend on external loads, environmental conditions, etc. A speed target of 1 mm/s will generate a roughly 1 mm/s motion, but it is not guaranteed.

Additionally, due to the way EPICS operates, setting VELO will not immediately send a command to the MD90. Instead, EPICS remembers the last value you set, and will set this new velocity target when it sends the next move command. However, the motor must not be in servo mode to accept a new velocity target.

The motor enters servo mode when you send a new position target, and stays in servo mode until you issue a Stop command (by setting the DSM:m0.STOP parameter to 1).

If you do not disable servo prior to issuing a Move command at the new velocity, then VELO will become out of sync with the actual motor velocity, and EPICS will return error 3 "Cannot execute while moving" in its console each time you issue a Move command. This is because each Move command internally sends a "Set step frequenc" command, which will error if you do not Stop the motor first. Reading the VELO parameter at this point will return the wrong value- it returns the value you requested, not the actual speed setting on the motor. To fix this, you must Stop the motor, then send a new Move command. At