Galil DMC-1700, DMC-1800 Hardware & Software Protection, Introduction, Hardware Protection

Chapter 8 Hardware & Software Protection

Introduction

The DMC-1700/1800 provides several hardware and software features to check for error conditions and to inhibit the motor on error. These features help protect the various system components from damage.

WARNING: Machinery in motion can be dangerous! It is the responsibility of the user to design effective error handling and safety protection as part of the machine. Since the DMC-1700/1800 is an integral part of the machine, the engineer should design his overall system with protection against a possible component failure on the DMC- 1700/1800. Galil shall not be liable or responsible for any incidental or consequential damages.

Hardware Protection

The DMC-1700/1800 includes hardware input and output protection lines for various error and mechanical limit conditions. These include:

Output Protection Lines

Amp Enable - This signal goes low when the motor off command is given, when the position error exceeds the value specified by the Error Limit (ER) command, or when off-on-error condition is enabled (OE1) and the abort command is given. Each axis amplifier has separate amplifier enable lines. This signal also goes low when the watch-dog timer is activated, or upon reset. Note: The standard configuration of the AEN signal is TTL active low. Both the polarity and the amplitude can be changed if you are using the ICM-1900 interface board. To make these changes, see section entitled ‘Amplifier Interface’ pg 3-47.

Error Output - The error output is a TTL signal which indicates an error condition in the controller. This signal is available on the interconnect module as ERROR. When the error signal is low, this indicates one of the following error conditions:

1.At least one axis has a position error greater than the error limit. The error limit is set by using the command ER.

2.The reset line on the controller is held low or is being affected by noise.

3.There is a failure on the controller and the processor is resetting itself.

4.There is a failure with the output IC which drives the error signal.

Input Protection Lines

General Abort - A low input stops commanded motion instantly without a controlled deceleration. For any axis in which the Off-On-Error function is enabled, the amplifiers will be disabled. This could cause the motor to ‘coast’ to

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