Panasonic MSM and Fanuc SL Series Motors with MFE2500 Encoders

Motor/Feedback Description –

The Fanuc SL series motors appear to have the same feedback and same alignment as the
Panasonic MSM motors, so in this discussion we will not distinguish one from the other.

These motors come both with incremental encoders that use a 15 pin Amp connector and 17 bit
serial absolute encoders that use a 9 pin Amp connector. In this document, we are discussing the
incremental encoder. It is a 2,500 pulse/rev (10,000 count/rev) incremental encoder with standard
A, B, and Z channels, but it also has a serial RX channel. The serial channel provides encoded
commutation signals, but the current tester software does not support using this RX channel.
However, the A, B, and Z incremental signals can be used to check and set commutation with the
TI-5000, TI-5000EX and TI-7000 or to run the motor with the TI-3000. Some suggestions on
checking the RX channel signals will be provided later in this document.

The TI-5053 cable is compatible with this feedback device.

The following information is known to be correct for a Panasonic MSM042A1G and a Fanuc
C800SLM075N2XE25B motor. It undoubtedly extends to other similar motors, but these were the
motors used to get the information. You should verify for yourself that this information is usable
for any similar motor you may have. These motors were 8 poles with a forward armature direction
of CW at the drive shaft end. Refer to the TI-5053 cable for feedback pinouts. The armature
connections for the 4 pin and 2 pin AMP connectors were as follows:

Pin       Function            Color
1          U                        RED
2          V                        WHI
3          W                       BLK
4          GND                   GRN
1           24V BRK            YEL
2           24V BRK            YEL

Alignment –

Lockup Polarity              Electrical Angle        Comm Signals

U        V         W                                               U       V       W

+         -                          120E                          H>L  H       L

+                    -               180E                          L        H       L>H

-                      +              0E                             H       L        H>L

TI-3000 Setup –

Feedback Manufacturer = Generic Encoder
Count/rev = 10,000
Poles = 8
Direction = A or S
+U –V Lockup Angle = 120 degrees

RX Channel Serial Data –

Along with the A, B, Z and complement lines, these encoders also have a RX and RX* lines.
These lines produce a U, V, W commutation type pattern as 8 bit serial data. At this time there is
no TI-5000 or TI-3000 support for these lines. However, they produce data all the time that can
be observed by connecting a scope to these lines. The bit pattern can be seen to change as the
encoder is rotated. It would be good to check for activity on these lines until support can be
developed for these signals.

The basic idea is similar to the Yaskawa C Channel encoders in that the three commutation
signals are encoded onto one pair of lines. However there are enough differences that this signal
cannot be decoded using Yaskawa C Channel support.

The signal on the RX line is described as follows:

1. The signal idle state is HI.
2. The data bit time is 1 µS.
3. There are 8 bits of data as follows: Start bit (always goes LO), W*, U*, V*, V, U, W, parity.
4. The time from one start bit to the next is 12 µS. This means that the data word takes 8 µS
and the idle time is 4 µS.

At a minimum, you will probably want to put a scope on the RX and RX* lines to verify that the
signals are present. You will also be able to see that they are the complement states of each
other.

If you are really industrious, you can try to visually decode the states as described in 3. above
and verify the commutation states at the lockup points as shown in the alignment information
above.