Page 14 Non-Sound Decoder MX618 - MX638 and Sound Decoder MX640 - MX659
Lastly there is a third kind of CV that sort of fits between the other two. Here you don’t have to worry
about Bits and their values. With those CV’s the digit’s position and value determines a specific ac-
tion. Some of those digit positions act like a simple ON/OFF switch and others like a volume control.
For example, CV #56 can be used for fine-tuning a motor:
CV
Denomination
Range
Default Description
#56
Back-EMF control
P and I value
0
– 199
(See add.
notes)
0
(is equal
to 55,
mid-
range)
But:
default is
not suita-
ble for
coreless
motors,
i.e.
MAXXON,
FAUL-
HABER!
Use
“100”
instead.
Back-EMF compensation is calculated by PID al-
gorithm (Proportional/Integral - Differential);
modifying these values may improve the com-
pensation characteristics in certain cases.
0 -
99: for „normal“ DC motors (LGB etc.)
100 - 199: for coreless (MAXXON, Faulhaber,
etc...)
Tens digit: Proportional (P) value; by
default (0) is set to mid value and
automatic adjustment with the goal
of jerk free running. Proportional
effect can be modified with settings
of 1
– 4 and 6 – 10 (instead of the
default 0 = 5).
Ones digit: Integral (I) value; is set by
default to a mid-value.
The Integral effect can be modified
with settings of 1
– 9 instead of
the default 0 = 5).
As you can see in the “Range” field you can use any number between 0 and 199. However if you read
the “Description” field it explains that each digit position controls a specific function. In this case, the
hundredth digit (_xx) sets the decoder up for a coreless motor, the tens digit (x_x) modifies the pro-
portional and the ones digit (xx_) the integral action. The hundredth digit acts just like a switch. If you
use the hundredth digit (1__) the coreless motor control
is turned ON. If you don’t use it (_xx), the
function is turned OFF. So for a normal DC motor you would only use the ones and tenth digit. With
the tens digit (0
– 9) you can modify the proportional value and with the ones digit (0 – 9) the integral
value.
Don’t worry about the terms “proportional” or “integral” - just use the
“Step by step CV adjustment
proce
dure”
later in the manual.
3.1
Programming in
“Service mode” (on programming track)
The decoder must be unlocked, before it is possible to program, with
CV #144 = 0
or
= 128 (
the latter prevents decoder updating but allows programming).
This is normally the case (CV #144 = 0), but the programming lock is often activated in many sound
projects to prevent accidental changes. It is therefore useful to check this CV, especially when pro-
gramming attempts have already failed.
Acknowledgments of successful programming steps as well as CV read-outs on the programming
track are accomplished by power pulses, which the decoder generates by briefly actuating the motor
and/or headlights. If the motor and/or headlights do not draw power (i.e. they are not connected) or
the power draw is too low, acknowledgments for successful programming or CV read-outs are not
possible.
To make acknowledgments possible in such cases activate CV #112 bit 1, which enables the decoder
to use an alternate acknowledgment method by sending high frequency pulses from the motor power
amplifier. It depends on the digital system in use, if this procedure is successful or not.
CV
Denomination
Range
Default Description
#144
Programming and
Update Lock
Note: The programming
lock has no effect on
CV #144 and is there-
fore always accessible
for unlocking.
Bits
6, 7
0
or
255
= 0: Decoder unlocked. Free programming and
updating is possible.
Bit 6 = 1: Decoder p
rogramming in „Service Mode“ is
blocked to prevent unwanted programming.
Note: Programming in
“Operations Mode“ is not
locked because any such programming only
applies to the active loco address and
reprogramming the wrong locomotive is
therefore not possible.
Bit 7 = 1: Software updates via MXDECUP, MX31ZL or
other means are blocked.
#112
Special ZIMO
configuration bits
0 - 255
4 =
00000100
that is
Bit 1 = 0
(normal)
Bit 1 = 0: Normal acknowledgment in
“Service Mode“;
motor and headlight pulses.
= 1: High frequency pulses instead of normal
acknowledgments from motor and headlights.
Bit 2 = 0: Loco number ID is OFF
etc.
Attention:
The CV values of sound decoders at time of delivery do not correspond with the default
values in the following chapters, but rather the initial values of
each loaded sound project!
This applies most often to
CV #29
– analog operation is usually turned off (Bit 3 = 0); CV #29 = 14 turns this on if desired.
CV #144
– the update lock may be activated (Bit 7 = 1), sometimes even the programming lock (Bit 6
= 1); before updating or programming a decoder, set this CV to CV #144 = 0.
CV #3, 4
– acceleration and deceleration CV’s are often set to higher values (i.e. 12).
CV #33 and following
– the functions are often mapped to a specific loco model...
…and of course the sound CV’s (from CV #265) and (less frequently) all other CV’s.
