Things To Consider Before Retrofitting A Servo

---

Make sure you understand:

• What is the runtime & criticality: % run per day (or) week (or) month?
• What are the features of the environment (heat, contamination, moisture, etc.)?

NOTE: Refer to a previous LinkedIn post from our teammate #AutumnMatian regarding the dangers of conductive dust and the need to keep enclosures clean. Click Here for link

---

Are you aware of the duty: 

• Speed Rating
  How often is it in each speed range?
• Torque
  How often is it in each range?
• Power
  How often is it using most of its torque at most of it speed?
• Braking Or Speed Reversal
  How often is it changing direction or slowing under high load?

---

Things to know about the Drive (output shaft):

• Is it connected to a gear box (matching bolt pattern and shaft size will be needed unless entire servo/gearbox is replaced as a set)?
• Is it connected to a chain or belt drive (results are more flexible in options most of the time)?

---

Size:

• Does the currently installed location allow for enough room for something a bit longer or a bit larger in diameter if you cannot secure a replacement of the same dimensions?

---

Electrical:

• Matching the input power from old to new will minimize the cost.
• Make sure the current does not draw more Amps than the current version.  

---

Control, Software, and Programming:

• The most likely scenario of minimizing expense is to maintain the manufacturer and model.
• Ensure instructions are available for the current PLC and the intended new servo controller. Having these is critical to ensuring compatibility. If there’s no compatibility, you’ll be taking on a project involving a complete re-write of the code’s full control section.

---

Communication Protocols:

• Will the new servo communicate with the system (if it’s not an exact replacement)?
• The PLC requires the correct add on instruction to communicate correctly.
• The PLC code needs to be sequenced properly (depending upon the drive) so move instructions and commands operate correctly.
• The faults need to be configured so the PLC is aware of the state of the servo drive (i.e. whether the servo is homed or faulted).
• The drive itself needs to be configured with settings to determine how it homes and what internal values it will use to measure its position.  

---

Electrical Install:

• Is there room in the enclosure for a different larger control?
• Is there enough cooling for any added brake resistors?
• Is there an allowance for adequate wiring from the controller to the motor (plug and cable length, as wells as the plug and cable penetration through the enclosure wall)?