Non-Sound Decoder MX600 - MX638 and Sound Decoder MX640 - MX659 Page 17
track voltage collapses when the decoder (motor) starts to draw power which, in the worst case, may
lead to intermittent performance.
There are some adjustment possibilities for analog operation where motor control and function out-
puts are concerned; these CV’s can of course be read-out or programmed only with a DCC system or
other programming device.
CV
Denomination
Range
Default
Description
#29
Basic Configuration
0 - 63
14 =
0000 1
1
10
Bit 2 = 1
(enables
analog op-
eration)
Bit 0 - Train direction:
0 = normal, 1 = reversed
Bit 1 - Number of speed steps:
0 = 14, 1 = 28
Bit 2
– Automatic DC operation (analog): *)
0 = disabled 1 = enabled
Bit 3 -
RailCom („bidirectional communication“)
0 = deactivated 1 = activated
Bit 4 - Individual speed table:
0 = off, CV # 2, 5 and 6 are active.
1 = o
n, according to CV ‘s # 67 – 94
Bit 5 - Decoder address selection:
0 = short address as per CV #1
1 = long address as per CV #17+18
#13
Analog functions
F1…F8
0 - 255
0
Defines functions
that should be “ON” in analog mode.
Bit 0 = 0: F1 is OFF in analog mode
= 1: …ON in analog mode
Bit 1 = 0: F2 is OFF in analog mode
Bit 1 = 1: …ON in analog mode
………..F3, F4, F5, F6, F7
Bit 7 = 0: F8 is OFF in analog mode
Bit
7 = 1: …ON in analog mode
#14
Analog functions
F0 v&r, F9
– F12,
Analog momentum
and
Regulated Analog
0 - 255
64
(equals
Bit 6 = 1)
Defines function outputs that should be “ON” in analog
mode.
Bit 0 = 0: F0 (forw) is OFF in analog mode
=
1: …ON in analog mode
Bit 1 = 0: F0 (rev) is OFF in analog mode
Bit 1 = 1: …ON in analog mode
Bit 2 = 0: F9 is OFF in analog mode
Bit 2 = 1: …ON in analog mode
------------F10, F11, F12
Bit 6 = 0: Analog operation with acceleration and
deceleration according to CV #3 and #4,
especially useful for sound
Bit 6 = 1: Analog operation without acceleration and
deceleration according to CV #3 and #4.
Bit 7 = 0: unregulated DC operation
Bit 7 = 1: regulated DC operation
Note: Actual decoder settings may differ from the default values if a sound project is on the decoder; in particular,
the motor regulation (CV #14, Bit 7) is often enabled. The regulation only works well with power packs that apply
“clean” DC voltage (i.e. with an LGB 50 080); otherwise it is better to turn the motor regulation off.
3.6
Motor Regulation
The speed curve
There are two types of speed curves, which are selected with
CV #29, Bit 4
= 0
: 3-step curve (defined by
3 CV’s)
... = 1
: 28-step curve (defined by
28 CV’s)
3-point speed table: the lowest, highest and medium speed is defined by the Configuration Variables
#2 (Vstart), #5 (Vhigh) and #6 (Vmid) (=external speed step defined by slider position). This is a sim-
ple way to quickly establish a speed range and its curvature.
The three-step curve is usually sufficient.
28-point speed table (a.k.a.
”free programmable speed table”): with the help of CV’s #67 - 94, all 28
exter
nal speed steps can be freely assigned to the 128 internal speed steps. These 28 CV’s apply to
all speed step modes (14, 28 and 128). If 128 external speed steps are used, the decoder adds the
missing intermediate values by interpolation.
CV
Denomination
Range
Default
Description
#2
Start Voltage
Vstart
with 3-point table if
CV #29, Bit 4 = 0
1 - 255
1
Internal speed step
(1 … 255) applied as
lowest
external speed step (= speed step 1)
(applies to 14, 28, or 128 speed step modes)
= 1: lowest possible speed
#5
Top Speed
Vhigh
with 3-step curve if
CV #29, Bit 4 = 0
0 - 255
0, 1
corresponds
to
255
Internal speed step (1 … 255) applied as
highest
external speed step
(14, 25 or 128, depending on the speed step mode
selected in CV # 29, Bit 1)
=0 = 1 (same as 255): fastest top speed possible.
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
0 1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19
20 21 22 23 24 25 26 27 28
0 9 18 27 36 45 54 63 72 81 90 99 108 117 1
26
Example of a freely
programmed speed
curve according to
the values entered
in to configuration
variables #67 - 94.
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
20 21 22 23 24 25 26 27 28
0 9 18 27 36 45 54 63 72 81 90 99 108 117 1
26
Clipped and bent speed curve
Vstart = 15, Vhigh = 180, Vmid = 60
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
20 21 22 23 24 25 26 27 28
0 9 18 27 36 45 54 63 72 81 90 99 108 117 1
26
Clipped linear speed curve
Vstart = 10, Vhigh = 165,
Vmid = 90
150
160
170
180
190
200
210
220
230
240
250
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
0 9 18 27 36 45 54 63 72 81 90 99 108 117 1
26
Lin
ear
ch
ara
cte
risi
tc
- V
sta
rt=
1, V
hig
h=
25
2,
Vm
id=
12
7
Slightly bent
(default) characterisitc
Vmid = 1 (equals 85)
Vstart = 2
Vhigh = 1
(equals 252)
Center
150
160
170
180
190
200
210
220
230
240
250
In
te
rn
a
l
s
p
e
e
d
s
te
p
External speed step
