DESCRIPTION

spec supports the Sigmatech model FC-501A motor controller over GPIB and RS-232C interfaces. The FC-501A controller comes with one or two axes and performs positioning to 10 nm resolution with optional closed-loop control. Multiple units can be configured.

DEVICE CONFIGURATION

Configure the motor controllers on the Devices screen of the configuration editor as follows, choosing the GPIB or serial entry, as appropriate.

Motor and Counter Device Configuration (Not CAMAC)

 MOTORS     DEVICE   ADDR <>MODE NUM                          <>TYPE
    YES                 4          2        Sigmatech FC-501A (GPIB)
    YES /dev/ttyS0     <>   9600   2      Sigmatech FC-501A (Serial)

Choose FC501A as the controller type on the Motorscreen of the configuration editor.

PARAMETERS

A number of parameters associated with the Sigmatech motors can only be set using the device front-panel controls. There is no software access to these parameters, either for reading or writing. See the Sigmatech manual for details. Of the standard motor parameters available in the spec configuration editor, the steady-state rate and acceleration are used, but the base rate is not.

Home searches are available with the controller, and the standard optional motor parameter "home_position" will be used, if set. See the home search discussion below.

The standard optional parameter for read-back "slop" is useful to set in closed-loop mode. Position discrepancies less than the slop value (in steps) will be silently remedied in favor of the controller.

A non-standard optional motor parameter "control_mode" is recognized by this controller to set open-loop or one of two possible closed-loop control modes. Type a <p> from the main Motor screen of the configuration editor to reach the nonstandard optional parameter page. Type a <H> there for instructions on entering such parameters. See below for parameter values.

The following parameters are set using the motor_par() function.

motor_par(mne, "input")

Returns a value representing the general-purpose digital input port status.

motor_par(mne, "output", value)

Sets the general-purpose digital output port to value.

motor_par(mne, "control_mode" [, arg])

Returns or sets the stage control mode, which is described in the controller documentation as one of open-loop, closed-loop mode 1 or closed-loop mode 2. The argument arg can be one of the strings "open", "closed_1" or "closed_2" or corresponding numeric values of 0, 1 or 2. The return value will be 0, 1 or 2. If this parameter is set as a non-standard optional motor parameter in the hardware config file, spec will send the value on startup and on reconfig.

motor_par(mne, "send", cmd)

Sends the string cmd to the FC-501A controller associated with mne.

motor_par(mne, "read", cmd)

Sends the string cmd to the FC-501A controller associated with mne, and returns the reply.

HOME SEARCH

Home search is implemented. At the end of the search, the dial position will be set to the value of the standard optional motor parameter "home_position", if that parameter is set. Otherwise, the home position will be set to zero. In addition, a third argument to the chg_dial() function or a second argument to the standard home macro can specify the dial home position, overriding the value set for the "home_position" parameter.

Home searches can be conducted (for a motor m0) using:

home m0; uwm m0

To set the position at the end of the search, use:

home m0 5