Applies to

• VLF Platesetter
• VLF Trendsetter
• Platesetter 3244
• Trendsetter 3244

Description

Causes

• Drum velocity is not constant
• Encoder misreading the drum speed
• Hall sensors misreading the drum speed
• VLF drum PID settings incorrect

Solutions

Drum velocity is not constant

Try to determine if this is the cause by listening to the sound of the acceleration. If the speed appears to waiver in tone:

• Make sure the drum amp dead band is not too narrow:
  drum cal
  Note: The command drum cal only works for drum firmware module 1.09 and higher. To check the module version, use the command list version.

• Make sure the main 220VAC power source is not too low. Check the power connections to the drive amp by checking the voltage at the drive amp. (J1-3 and J1-4)

• If the error was as a result of a drum spin command, check the PID constants (drum pgv, drum igv, and drum dgv; drum pgr, drum igr, and drum dgr). These NVS parameters should be at their default or close to it. Do not change without advice from Creo engineering.

• If the error was as a result of a drum spin xx c command, check the PID constants (drum pgh, drum igh and drum dgh). These NVS parameters should be at their default or close to it. Do not change without advice from Creo engineering.

Encoder misreading the drum speed

This is only valid when the error occurs during a plot or drum spin xx command.

• Clean the encoder disk and encoder block.
  See Optical encoder cleaning procedure

• Check the encoder block alignment.
  See Checking the optical encoder and Optical Encoder Alignment Procedure.

• Make sure that the drum is properly balanced. (VLF Platesetter and VLF Trendsetter only).

• Make sure the encoder disk is not off center (not common).

Hall sensors misreading the drum speed

This is only valid when the error occurs during a drum init or drum spin xx c command.

• Check the motor hall sensor cable

• Make sure the 5V power into J3 pin 5 is not flaky (VLF only)

• Inspect connector pins at J3

• Enter the command drum cal.
  Note: The command drum cal only works for drum firmware module 1.09 and higher. To check the module version, use the command list version.
  If the drive amp's dead band has become too wide or too narrow, this command generates an error message. In this case, replace or recalibrate the drive amp. See CTP Firmware Drum Amplifier Dead-Band Calibration.

• Check that the belt has not come very loose and that the pulley is not slipping on the shaft.

VLF drum PID settings incorrect

Some VLF systems may have the wrong drum PID settings. Try the settings below. If they do not worsen the situation, then save them.

"set drum <...>"
pgv = 25000
igv = 600
dgv = 0
pgr = 25000
igr = 600
dgr = 0

See also

• Drum: timeout on velocity acceleration (6008)
• General VLF drum drive, encoder, and PLL troubleshooting
• Firmware documentation
• Understanding Dependancies of Hall Sensors and Encoder
• Device fails drum initialization