Electro Cam PL-1746 Series - Manual (Page 108)

7-3 Troubleshooting
Resolver Troubleshooting
Mechanical Problems If the resolver is generating erratic RPM or position readings, or the position appears to
be shifting periodically with respect to the machine cycle, check the mechanical cou-
pling between the resolver and the machine.
If the coupling is not slipping, loosen the coupling and rotate the resolver shaft in both
directions with sudden, jerky motions. If the controller displays unusual position or RPM
readings, the resolver may be need to be replaced.
Resolvers cannot be repaired in the field. If a unit fails, do not disassemble it.
Return it to the factory for replacement.
Electrical Problems If any wire in one of the three individually shielded pairs becomes disconnected, the
following error message will appear on the keypad/display:
ERROR: RESOLVER
NOT CONNECTED!
The output channels will immediately be disabled until the resolver is reconnected.
Press ESC to clear the error message.
Note that ESC will clear the message and restore access to keypad programming
even if the resolver has not been reconnected.
Follow this procedure to troubleshoot electrical problems:
1. Verify that the electrical connections at each end of the resolver cable are secure.
2. Disconnect the cable at the controller. Measure the resistances between all wires
on the terminal block. The paired wires should have the resistances shown in the
table below, while the resistance between every other combination of wires should
be infinite. If the resistances are correct, the controller may need to be replaced.
3. If the resistances in Step 2 are incorrect, the problem may be in the cable or in the
resolver. Disconnect the cable at the resolver and measure the resistances at the
resolver pins. If the resistances are correct, the cable is bad. If the resistances are
wrong, the resolver should be replaced.
Wire Pair Resistance or Resistance
White/Black 15 to 25 Ohms 60 to 85 Ohms
Red/Black 20 to 40 Ohms 135 to 185 Ohms
Green/Black 20 to 40 Ohms 135 to 185 Ohms
Note: The resolver resistance will fall into one set of ranges or the other, depend-
ing on the date of manufacture.
When the COMM PORT diagnostic is run with keypad
terminals W, X, Y, and Z jumpered as shown, a string
of “plus” signs will scroll across the display. When
either jumper is removed, the scrolling will stop.
Keypad Communications Port Test Setup
PS-6400 Keypad Troubleshooting (cont'd)