RMS Technologies IMD23 W/ POLE DAMPING TECHNOLOGY - Manual (Page 20)

RMS Technologies Page 20 Version 1.10
IMD23/23DE Manual 12/3/2007
BASIC STEP AND DIRECTION OPERATION
The three control signals Step, Direction, and Disable, are optically isolated, with a common
positive connection (usually 5 VDC).
The common positive connection (Pin 8) is typically 5 VDC. Each of the inputs is set to TRUE
by supplying a signal level 5V below the common positive connection powering the optical
isolators. The input is set FALSE by putting the signal within 0.5 VDC below the common
positive value.
Example: If 5 VDC is supplied to Pin 8 (common positive connection), TRUE is 0V, and
FALSE is any value between 4.5 VDC to 5 VDC.
For test purposes, and some applications where input isolation is not required, the internal 5
VDC supply at Pin 3 of the I/O connector can be used as the common positive connection,
by linking pins 3 and 8 on the connector.
If this is done then each input is set TRUE by bringing the voltage level at the input equal
to, or more negative than the Power Supply negative connection at Pin 2 and 7.
With this arrangement Direction and Disable control can be effected by simple switch
closure between the input and the power negative connection at Pin 2 and 7.
If the Step input is obtained from a Function Generator, then careful adjustment of the
Offset control is needed to ensure that the negative level of the input signal is equal to, or
more negative than, the power negative connection at Pin 2 and 7.
The minimum duration of the active (negative) Step input signal level is 200 nanoseconds
and also this is the minimum for the inactive (positive) level. This limits the maximum
usable step rate to 2.5 MHz.
The optimum operating arrangement (minimum power usage) is for a constant width
negative going pulse of 200 nanoseconds with the pulse interval varying with pulse rate.
For test purposes, setting the Function Generator duty cycle to 50%, and just varying
frequency is satisfactory.