NI identifies the NI 7340 as a combination servo and stepper motor controller, and the user manual explicitly covers the NI PXI-7340 or PCI-7340 motion controller. The PXI-7340 is therefore a primary controller module rather than an accessory, and NI states that the 7340 motion controller provides motion control for up to four independent or coordinated axes. Source: https://download.ni.com/support/manuals/370838b.pdf
For motion functions, NI specifies ±10 V analog command outputs for servo operation. For stepper control, the controller supports step/direction or CW/CCW outputs with a maximum pulse rate of 4 MHz and output voltage of 0 to 5 V. NI also specifies quadrature, incremental, single-ended encoder inputs with a 20 MHz maximum count rate, plus dedicated per-axis motion I/O including limit and home inputs, breakpoint outputs, trigger inputs, and encoder feedback. Source: https://download.ni.com/support/manuals/370838b.pdf
The PXI-7340 also integrates onboard processing and general-purpose I/O resources. NI specifies a 32-bit CPU, DSP, and custom FPGAs, with onboard execution of up to 10 simultaneous motion programs. The hardware includes 32 bits of digital I/O, four user analog inputs within a bank of eight multiplexed single-ended analog inputs, four single-ended analog outputs rated at ±10 V and 16-bit resolution, and two PWM outputs up to 50 kHz with 8-bit resolution. Source: https://download.ni.com/support/manuals/370838b.pdf