Galil DMC-1700, DMC-1800 Microcomputer Section, Motor Interface, Communication, General I/O

DMA/DPRAM

2ND FIFO

Primary

FIFOS

Interrupts

ISA/PCI BUS

WATCHDOG TIMER

68331

MICROCOMPUTER WITH

4 Meg RAM

4 Meg FLASH EEPROM

I/O INTERFACE

HIGH-SPEED

MOTOR/ENCODER

INTERFACE

FOR X,Y,Z,W, etc.

ISOLATED LIMITS AND

HOME INPUTS

MAIN ENCODERS

AUXILIARY ENCODERS

+/- 10 VOLT OUTPUT FOR SERVO MOTORS PULSE/DIRECTION OUTPUT FOR STEP MOTORS

HIGH SPEED ENCODER

COMPARE OUTPUT

8 UNCOMMITTED	8 PROGRAMMABLE,	8 PROGRAMMABLE
ANALOG INPUTS	OPTOISOLATED	OUTPUTS
	INPUTS

HIGH-SPEED LATCH FOR EACH AXIS

Figure 1.1 - DMC-1700/1800 Functional Elements

Microcomputer Section

The main processing unit of the controller is a specialized 32-bit Motorola 68331 Series Microcomputer with 512K byte RAM and 512K byte Flash EEPROM. The RAM provides memory for variables, array elements, and application programs. The flash EEPROM provides non-volatile storage of variables, programs, and arrays. The Flash also contains the firmware of the controller, which is field upgradeable.

Motor Interface

Galil’s GL-1800 custom, sub-micron gate array performs quadrature decoding of each encoder at up to 12 MHz. For standard servo operation, the controller generates a +/-10 Volt analog signal (16 Bit DAC). For sinusoidal commutation operation, the controller uses 2 DACs to generate 2 +/-10Volt analog signals. For stepper motor operation the controller generates a step and direction signal.

Communication

The communication interface with the host PC contains a primary and secondary communication channel. The primary channel uses a bi-directional FIFO and includes PC interrupt handling circuitry. The secondary channel can be set as DMA or DPRAM where data is placed in PC memory or as a Polling FIFO where data is placed into the controller’s FIFO buffer. The DMA is available on the DMC-1700 and, DPRAM is only available on the DMC- 1800 (1810-1840 Rev H and greater, DMC-1850-1880 Rev E and greater), whereas the Polling FIFO is available on both the DMC-1700 and DMC-1800.

General I/O

The controller provides interface circuitry for 8 bi-directional, optoisolated inputs, 8 TTL outputs, and 8 analog inputs with 12-Bit ADC (16-bit optional). The general inputs can also be used for triggering a high-speed positional latch for each axis.

Each axis on the controller has 2 encoders, the main encoder and an auxiliary encoder. Each unused auxiliary encoder provides 2 additional inputs available for general use (except when configured for stepper motor operation).

DMC-1700/1800 Chapter 1 Overview • 3