DESCRIPTION

The PMC Corporation DCX-100 motor controller is an ISA PC card that has eight module positions. All eight modules can be used to control individual motors or one of the modules can instead be an RS-232C interface. spec can control the DCX-100 cards either locally using the ISA memory-mapped interface or else remotely over the RS-232C interface. In the latter case, the send, receive and ground signals of the RS-232C interface modules from each of multiple boards can be wired in parallel, and all can be controlled by spec through one serial port of the controlling computer. (Other module configurations are possible, but are not currently supported by spec.) (Note, the DCX-100 boards are used as OEM components in motor controllers sold by the Dynaoptic Motion company.)

The controller is selected on the edconf devices screen along the lines of:

MOTORS      DEVICE   ADDR <>MODE  NUM                     <>TYPE
   YES             0xd000           8  PMC Corp DCX-100 PC Board
   YES  /dev/ttyS0     <>   9600   16  PMC Corp DCX-100 (Serial)

The config file will have:

PC_DCX = mem_map_address number_of_motors

RS_DCX = device_name baud_rate number_of_motors

for the above two configurations.

For the PC board configuration, the memory-mapping address is selected by the on-board rotary switch SW1. Position 0 corresponds to address 0xd000, position 1 corresponds to address 0xd100, etc. For the serial (or RS-232C) configuration, boards are also selected by address. That address is used for the individual motor channel configuration as follows.

DCX motors on serial ports require unit/channel configuration. Unit numbers are assigned to each DCX controller in the order they appear on the Device screen, starting with unit 0. Channel numbers are of the form X1 to X8 where X is the board number, matching the SW1 setting, and the number is module number on the board.

MOTOR PARAMETERS

spec allows a number of additional parameters to be set in the configuration file and by the motor_par() function for these controllers. Use the configuration editor to establish the long-term values of the parameters in the configuration file. Use motor_par() to make changes to the parameters that only are in effect during a particular spec session. To set the parameters from the configuration editor, use the m command from the main motor screen to access the optional-parameter screens.

The following parameters are associated with DC motor operation. The two-letter command sent to the motor controller associated with each parameter is given in parenthesis.

motor_par(motor, "dc_proportional_gain" [, value])

If value is given, sets the proportional gain, otherwise returns the current value. ("SG")

motor_par(motor, "dc_derivative_gain" [, value])

If value is given, sets the derivative gain, otherwise returns the current value. ("SD")

motor_par(motor, "dc_integral_gain" [, value])

If value is given, sets the integral gain, otherwise returns the current value. ("SI")

motor_par(motor, "dc_integration_limit" [, value])

If value is given, sets the integration limit, otherwise returns the current value. ("IL")

motor_par(motor, "dc_sampling_interval" [, value])

If value is given, sets the derivative sampling interval, otherwise returns the current value. ("FR")

motor_par(motor, "dc_following_error" [, value])

If value is given, sets the following-error threshold, otherwise returns the current value. ("SE")

To set the gain for the tth motor, for example, use

motor_par(tth, "dc_proportional_gain", 1000)

The function

motor_par(tth, "dc_proportional_gain")

returns the current value of the "dc_proportional_gain" parameter.

SPECIAL COMMANDS

motor_par(motor, "wdelay" [, value])

If value is given, sets the delay before writing a command to value microseconds, otherwise returns the current value. The default value is 20000 (20 msec).

motor_par(motor, "rdelay" [, value])

If value is given, sets the delay before reading a response to value microseconds, otherwise returns the current value. The default value is 50000 (50 msec).

motor_par(motor, "status_bits")

Returns the value returned by the controller's TS command.

motor_par(motor, "send", cmd)

Sends the string cmd to the DCX unit associated with motor.

motor_par(motor, "read", cmd)

Sends the string cmd to the DCX unit associated with motor, as above, and returns a string containing the response.

motor_par(motor, "usend", cmd)

Sends the string cmd to the DCX unit associated with motor, but doesn't address the command to a specific motor or add a line terminator. Thus cmd must include the full DCX command syntax.

motor_par(motor, "uread", cmd)

Sends the string cmd to the DCX unit associated with motor, as above, and returns a string containing the response.