Pulse Restrictions

The maximum allowable command velocity (pulse rate) is determined by the drive/motor specifications, the SynqNet node hardware's maximum pulse frequency, and the maximum duty cycle for the specified pulse width. When configuring the pulse width, make sure the maximum commanded velocity does not generate a pulse period that is less than 2x the pulse width. For example, if the maximum velocity is 100 kHz, the pulse width must not be greater than 5 microseconds. If the pulse width is too large for the commanded velocity, unstable behavior will result. The pulse width also cannot be set to greater than half of the sample period. For example, if the sample period is set at 2kHz (500 microseconds), then the maximum allowable pulse width would be 250 microseconds.

The minimum pulse width is 60ns. The width can be increased in 100ns increments, up to 1.00006 milliseconds, as long as the pulse width is not greater than half the sample period.

The following table shows the shortest and longest valid pulse width values:

If the programmed pulse width falls between 100ns increments, the next lower pulse width will be used. For example, programming a pulse width of 100ns will result in 60ns pulses; 200ns will result in 160ns pulses, etc.

The pulse error status bit (see MEIMotorStatus) will indicate if an incorrect pulse command was sent. If an incorrect profile is suspected (i.e. missing pulses), the user must read the status bit to verify an incorrect profile.

To correct pulse command violations the user must verify and adjust the maximum velocity and pulse width values in their system.