Insertion Device Serial Control Interface

This document describes the details of the Insertion Device control directly through a serial interface.

We have implemented a direct link between the IOC controlling the Insertion Device and the Beamline control system through a serial link.  The protocol is straight RS232 communications. The link between the IOC and the beamline is via a fiber optic cable and a fiber modem.  The user can connect the fiber modem which has a DB25 male to a computer serial port.

We will be using the Blue and White fibers from the MSL fiber bundle.  The Blue fiber will be used for Transmit (T) and the white for Receive (R) on the fiber modem. The modem will be set to the DTE modem for communications to a computer (This depends on the type of cable used between  the computer and fiber modem. The port parameters are  19200 baud, 8 bit and N parity and 1 stop bit with XON/XOFF protocol.

This software running on the IOC monitors the port at all times. All inputs from the serial port has to be terminated with only a carriage return (0xD). The IOC listens to the port and upon receiving a string with the CR delimiter immediately processes the command and depending on the request will act on it. An acknowledgment is always sent with a CR delimiter. When the program is ready it will send a message Program Ready.

The device control is only possible when the device is in User Mode. Requests for status is always available. When an unrecognized command is sent the program will respond with a message Unknown Command!!

Listed below are all the commands and their responses:
 

Control Process Variables

• GapSet=xxx.xxx

Reply : IDxx:Message1          Operating Range : 11.0 - 200.0              Unit : mm
Sets the average desired gap position of the insertion device.
• TaperGapSet=xxx.xxx

Reply : IDxx:Message1             Operating Range : 0.000 - 5.000              Unit : mm
Sets desired Taper amount about the average gap.  For normal Operation this value should be set to zero.
• ScanGap=xxx.xxx

Reply : IDxx:Message1            Operating Range : 11.0 - 200.0              Unit : mm
Set this for scanning of the device in terms of average gap. The device starts to move upon entering a value in this field.
• ScanEnergy=xxx.xxx

Reply : IDxx:Message2              Operating Range : 2.7 - 100.0              Unit : keV
Set this for scanning the device in terms of the energy for the specified harmonic. The harmonic value is used for the energy to gap conversion.  The device starts the move upon entering a value in this field.
• EnergySet=xxx.xxx

Reply : IDxx:Message2            Operating Range : 2.7 - 100.0              Unit : keV
Sets the ID gap by entering the desired energy for the specified harmonic. The gap position is calculated based on the selected energy.
• TaperEnergySet=xxx.xxx

Reply : IDxx:Message2              Operating Range : variable              Unit : keV
Sets the desired amount of energy spread about the average energy for the specified harmonic.
• HarmonicValue=n

Reply: IDxx:Message2            Operating Range : 1 to 7
This sets the harmonic value for gap-energy calculation.
• DeadbandGap=xxxx
Reply: IDxx:Message1            Operating Range : 0-1000          Unit : microns
This sets the Dead band gap.
• Start=1
Reply: IDxx:Message1            Operating Range : 1
Send the above command to start moving the device.
• Stop=1
Reply: IDxx:Message1            Operating Range : 1
Send the above command to stop all motion of the device.

Read Commands

• Gap

Monitor  the current average gap position in mm.
• TaperGap

Monitor the current taper amount of gap in mm.
• Energy

Monitor the current average energy for the specified harmonic in keV .
• TaperEnergy

Monitor the current amount of tapered energy for the specified harmonic in keV.
• Busy

Monitor  to determine whether the device is moving.  Reply is Moving or Done Moving
• HarmonicValue

Read the current Harmonic value chosen for the gap-energy calculations..
• DeadbandGap

Read the current deadband gap in microns.
• Message1

Monitor for all status and error messages.
• Message2

Monitor  for  status message related to gap - energy conversions and all global information.
• Message3

Monitor for status message related to Auto Open of ID when front end shutters are closed.
• ShClosedTime

Monitor the count down timer and displays the time left in seconds before ID will be opened automatically.
• TotalPower

Read the calculated total power in Watts from the device normalized to 100 ma for the current gap.
• ExpectedPower

Read the calculated total power in Watts from the device normalized to 100 ma for the desired gap entered.
• AccessSecurity

Monitor the current access mode. When in User the control has been transferred to user.
The following modes are the modes:
User
Operator
Floor Coordinator
Machine Physics
System Manager
• ID$(xx):DeviceLimit

Read to determine the beamline closed gap limit in mm  for the device. This is an administrative limit set by Floor Coordinator upon request from beamline coordinator.
• srCurrent

Read the storage ring current in ma.
• srLifetime

Read the storage ring Beam lifetime in hours.
• ActualMode

Read Operating Mode of the Storage ring.
• ShutterPermit

Read the shutter permit as enabled or disabled.
• IDFEShutter

Read the ID front end shutter status as closed or open.