Galil DMC-1700, DMC-1800 user manual Watch Dog Timer

either single-ended (CHA and CHB) or differential (CHA, CHA-, CHB, CHB-). The controller decodes either type into quadrature states or four times the number of cycles. Encoders may also have a third channel (or index) for synchronization.

The DMC-1700/1800 can also interface to encoders with pulse and direction signals. Refer to the “CE” command in the command reference for details.

There is no limit on encoder line density; however, the input frequency to the controller must not exceed 3,000,000 full encoder cycles/second (12,000,000 quadrature counts/sec). For example, if the encoder line density is 10,000 cycles per inch, the maximum speed is 300 inches/second. If higher encoder frequency is required, please consult the factory.

The standard encoder voltage level is TTL (0-5v), however, voltage levels up to 12 Volts are acceptable. (If using differential signals, 12 Volts can be input directly to the DMC-1700/1800. Single-ended 12 Volt signals require a bias voltage input to the complementary inputs).

The DMC-1700/1800 can accept analog feedback (+/-10v) instead of an encoder for any axis. For more information see the command AF in the command reference.

To interface with other types of position sensors such as absolute encoders, Galil can customize the controller and command set. Please contact Galil to talk to one of our applications engineers about your particular system requirements.

Watch Dog Timer

The DMC-1700/1800 provides an internal watchdog timer which checks for proper microprocessor operation. The timer toggles the Amplifier Enable Output (AEN), which can be used to switch the amplifiers off in the event of a serious controller failure. The AEN output is normally high. During power-up and if the microprocessor ceases to function properly, the AEN output will go low. The error light for each axis will also turn on at this stage. A reset is required to restore the controller to normal operation. Consult the factory for a Return Materials Authorization (RMA) Number if your DMC-1700/1800 is damaged.

DMC-1700/1800 Chapter 1 Overview • 5