We recommend considering two options in upgrading:
IPA drive/controller
The IPA uses the AcroBasic programming language and it can certainly do anything the Zeta6000 could. The IPA has Ethernet TCP/IP communications and 2 analog inputs (no analog outputs) and has additional features (absolute encoder support, lower price than the Zeta6000 and Ethernet/IP for communications with Allen Bradley PLCs via Add On Instructions).
Related FAQ: Replacing S/ZETA/ES series step motors with BE servo motors
Servo motors do have advantages of:
They're more accurate because they're a closed loop system. Step motors can open loop and can stall/lose position and you don't know it without an encoder; by the time you add an encoder on the back of the motor, you're better off with a servo 99% of the time.
They run cooler and are more efficient because they only draw power as needed because it's an error driven system. Thus you're not using very much power when you're not moving; step motors with most drive are running at current when stationary. This makes step motors run hot.
Servo motors can run at higher speeds. Step motors top speeds are 50rps (3000rpm) (with very little torque to actually accel/decel the load) if it's a good stepper drive like the Gemini/Zeta. Servo motors can run at 83rps (5000rpm) and higher, increasing your machine throughput and decreasing per part cost.
Servo motors are quieter. Step motors are noisy at speeds above 10rps (600rpm).
New option: ACR7000 Stepper Drive/Controller:
The ACR7000 is a stepper drive controller using AcroBasic programming and has Ethernet communications.
It's available in 4axis, 24 volt input power, much smaller than the ZETA and is 4A output.
Due to the lower voltages, speeds may be limited. We do have newer step motors with low voltage windings for higher speeds.