Enabling and Disabling Axes

Only enabled axes are updated and there is a direct correspondence between the number of enabled axes and the fastest update rate allowed.

Number of Enabled Axes        (7330/40/90)	Fastest Update Rate	Number of Enabled Axes        (7350)	Fastest Update Rate	Number of Enabled Axes        (NI SoftMotion Controller)	Fastest Host Loop Update Rate
1	62 µs	1–2	62 µs	1–8	10 ms
2	125 µs	3–4	125 µs	9–15	20 ms
3	188 µs	5–6	188 µs	16–23	30 ms
4	250 µs	7–8	250 µs	24–30	40 ms

The fastest update rate is achievable only when all axes are single-feedback servo axes and no extra encoders are enabled.

Caution  Update rates that are too fast for the number of axes, stepper outputs, and/or encoders enabled generates an error and the previous setting remains in effect.

The Enable Axis function automatically enables the feedback devices mapped to the enabled axes. It is not necessary to explicitly enable the encoders or ADC channels before enabling the axes. For NI 73xx devices, axes must be killed before they are disabled or the error NIMC_wrongModeError is generated. For the NI SoftMotion Controller it is not necessary to kill, or deactivate, an axis before disabling it.

Tip  Refer to Resource Allocation for information about using multiple resources on NI motion controllers.