ZIMO MS450, Instruction Manual

Page: 26 / 88

Page 26 MS - SOUND decoders MS440 to MS990 and MN - NON-SOUND decoders MN170 to MN340
The speed curves
There are two types of speed curves; between those select with
CV #29, bit 4 = 0
: 3-point speed curve (defined by 3 CVs)
... = 1
: 28-step curve (defined by 28 CVs)
3-point speed curve: the lowest, highest, and medium speed are defined by CVs #2 (Vstart), #5 (Vhigh)
and #6 (Vmid) (=external speed step defined by slider position). This is a simple way to quickly establish
a speed range and its curvature.
28-point speed curve (a.k.a.
”freely programmable speed curve”): with the help of CVs #67 - #94, all 28
external speed steps can be assigned freely to the internal speed steps (0-255). These 28 CVs 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.
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
Lin
ea
re
K
e
nn
lin
ie
-
V
st
ar
t=
1,
V
hi
g
h=
25
2,
V
m
id
=
12
7
Leicht
geknickte Kennlinie
(Default-Kennlinie)
Vmid = 1 (entspricht 85)
Vstart = 2
Vhigh = 1
(entspricht 252)
in
te
rn
e
F
ah
rs
tu
fe
externe Fahrstufe
Mitte
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
1
equals 255
Internal speed step (1 - 255)
applied as
highest external speed step
(i.e. for the external speed step 14, 28 or 128, depend-
ing on the speed step mode according to CV #29, bit 1
= 0)
= 0: equals 255 as highest speed step
=1: equals 255 as highest speed step
#6
Medium
Speed
Vmid
1 -
¼ to ½
of the
Value in
CV #5
1
(= @ 1/3
of top
speed)
Internal speed step (1 - 255) for medium external
speed step (i.e. for the external speed step 7, 14 or 64,
depending on the speed step mode 14, 28 or 128 ac-
cording to CV #29, bit 1)
”1" = default characteristic (medium speed is set to one
third of the top speed. I.e. if
CV #5 = 255: the curve is the same as if CV #6 would
be programmed to 85).
The speed curve resulting from CVs #2, #5 and #6
is automatically smoothed out, therefore no sharp
bends.
The average speed is reached in the first third of the
speed curve because it is not linear.
CV
Denomination Range Default Description
#29 Basic configuration 0 - 63
14 =
0000 1110
so bit 4 = 0
(3-point
Speed table)
Bit 0 - Train direction:
0 = normal, 1 = reversed
Bit 1 - Number of speed steps:
0 = 14, 1 = 28/128
Bit 2 - automatic change to analog operation
0 = disabled 1 = enabled
Bit 3 -
RailCom („bidirectional communication“)
0 = deactivated 1 = activated
Bit 4 - Individual speed table:
0 = off, CVs #2, #5 and #6 are active.
1 = on, according to CVs #67
– #94
Bit 5 - Decoder address:
0 = primary address as per CV #1
1 = ext. address as per CVs #17 & #18
#67
-
#94
Free (28-point)
speed table
if CV #29, bit 4 = 1
0 - 255 *)
internal speed steps (each 1-255) for each of the 28
external steps.
*) The 28-point default curve is also bent, emphasising
the lower speed range.
#66
#95
Directional speed trimming
0 - 127
0 - 127 0
0
Speed step multiplication by “n/128” (n is the trim value
in this CV): #66: for forward direction; #95: for reverse
direction
CV #57 - Voltage reference for the motor regulation
CV #57
specifies the reference value (voltage) used for motor regulation. For example: if 14 V is se-
lected (CV value: 140) the decoder tries to send the exact fraction of this voltage determined by the
position of the slider to the motor, regardless of the voltage level at the track. As a result, the speed
remains constant even if the track voltage fluctuates, provided the track voltage (more precisely, the rec-
tified and processed voltage inside the decoder, which is about 2 V lower) does not fall below the absolute
reference voltage.

The default value “0” in CV #57 selects the “relative reference”, which automatically adjusts the reference
voltage to the available track voltage. This setting is only useful, if the system can always keep the track
voltage constant (stabilized track output) and the resistance along the track kept to a minimum. All ZIMO
systems keep the track voltage stable - even older systems - but not every system from other manufactur-
ers do, especially relatively cheap systems built before 2005. It is not recommended to set CV #57 to “0”
with systems that do not keep track voltage stabilized. Instead set this CV to about 2 V below track voltage
(i.e. 140 for 16 V).

CV #57 can also be used as an alternative to CV #5 (top speed), which has the advantage that the full
resolution of the 255 speed steps remains available.
CV Denomination Range Default Description
#57 Voltage reference
0,
100 - 255
0
Absolute voltage in tenth of a volt applied to the motor
at full speed (max. throttle setting). A useful (and well
functioning) range is 10 to 24 V (i.e. 100-240), and
lower than the expected track voltage.
EXAMPLE: A system from another manufacturer is set
to 22 V at idle but drops to 16 V under load: A good
setting would be CV #57 = 140 - 150.
CV #57 = 0: automatically adapts to the track voltage
(relative reference); only useful with stabilized track
voltage.
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
Begrenzte lineare Kennlinie
Vstart = 10, Vhigh = 165,
Vmid = 90
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
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
Beispiel einer frei program-
mierten Geschwindigkeits-
kennlinie (entsprechende
Eintragungen in den Konfi-
gurationsvariablen # 67 - 94)