Page 52 Non-Sound Decoder MX618 - MX634 and Sound Decoder MX640 - MX648
Loco board
Decoder MX620N
6-pin
Loco socket
To tra c k
B row n
2 x bla c k
B lue (+ )
G re e n (-)
e.g.
Sm oke generator,
uncoupler etc.
M 4 0 0 0 Z
C o n n e ct to S U S I-C L OC K o r S U S I-D ATA so ld e r
p a d s o f th e M X 6 2 0 , co n ve rt th e o u tp u ts to fu n ctio n
o u tp u ts w ith C V # 1 2 4 , B it 7 .
Connecting DIETZ sound modules
without “SUSI” / “virtual cam sensor”
Consult the Dietz instruction manual regarding the installation and connection of their sound modules
to a ZIMO decoder.
For a good acoustic impression of steam engines, it is important that the chuffs are synchronized to
wheel revolutions. Therefore a cam sensor should be installed and connected to the sound module
(reed switch, optical or hall-effect sensor), which sends exactly 2 or 4 pulses to the module (depend-
ing on loco type).
If no cam sensor can be installed or an installation proves too difficult, many sound modules can also
generate their own chuff rate based on speed information (e.g. coming through the SUSI interface
from the decoder). The result is often poor with a chuff rate that is too fast at low speeds (the SUSI
protocol is not precise enough in that respect).
To improve this situation, ZIMO decoders come with a built-in
“virtual cam sensor”.
The function
output FO4 is used for this purpose,
converted to a “virtual cam sensor” function with the help of CV
#133 and connected with the cam sensor input of the sound module (e.g. Dietz, reed switch input);
this in addition to SUSI or other connections.
The virtual cam sensor is of course not capable of synchronizing chuff rates to wheel positions but ra-
ther to wheel speed, which is of little difference to the viewer.
The chuff rate of the “virtual cam sensor” can be adjusted to wheel revolutions with CV #267 and CV
#354; consult the CV table in ZIMO sound chapter.
Connecting of DIETZ or other sound modules with “SUSI”:
The SUSI interface developed by Dietz is an NMRA standard and defines the connection between
sound modules and loco decoders, provided the sound module is also equipped with such an inter-
face.
Due to space restrictions on small decoders, the SUSI interface composed of 4 conductors (2 data,
ground and power) is not built as a plug-in connector but instead uses
4 solder pads
(see decoder
drawings in the chapter “Technical specifications” in this manual).
Speed and load information (uphill, downhill, startup etc.), as well as programming values for the
sound module CV’s (#890…) are sent via the SUSI data lines (CLOCK and DATA) from the decoder
to the sound module.
Accessing SUSI CV’s in the SUSI module:
These CV’s are in the 890 range, according to the
standard (NMRA DCC Draft RP), which is not accessible with many DCC systems (ZIMO cabs MX2
and MX21 were also limited to 255 - until mid-2004). For this reason, ZIMO decoders allow access to
these CV’s with numbers in the 190’s!
Connecting an electric (un)coupler
(System “Krois”):
In order to prevent damage to the delicate core of an uncoupler from continuous power, appropriate
adjustments can be made with special CV’s for one or several function outputs.
First, write the value “48” to the special effect CV that is assigned to the same output an uncoupler is
connected to (e.g. CV #127 for output #1, CV #128 for output #2 etc.)
Next define a limit for the uncoupler’s activation time in CV #115 (see CV-table):
With the
“Krois uncouplers”
, it is recommended to use
a value of “60”, “70” or “80” for CV #115; this
means that the pull-
in voltage (full track voltage) is limited to 2, 3 or 4 seconds. A reduced “hold” volt-
age is not required for Krois, that’s why the ones digit is left at 0. Other uncouplers may need a re-
duced hold voltage though, like the ones from ROCO for example.
Regarding the “automated train disengagement” and/or “automatic coupler unloading” see
CV #116 in the chapter “Addressing and programming”, section “Configuration of Electric
Uncouplers”.
MX622R, MX623R,
MX630R… with NMRA 8-pin interface (NEM
652):
The “R” designated decoders come with an 8-pin plug mounted to
the end of its wires, which fits in to the socket of a DCC ready loco.
Remove the dummy connector from the socket and plug the de-
co
der in its place, that’s all.
All the necessary connections to power, motor and headlights are
established with this interface. Other outputs have to be hard wired.
MX621F, MX623F,
MX630F… with NMRA 6-pin interface (NEM
651):
The
“F” designated decoders come with a 6-pin plug mounted to the
end of its wires, which fits into the socket of a DCC ready loco.
The brightness of the headlight is reduced since the blue wire
(common supply) is not part of this interface. The light bulbs get
their power directly from the power pick up.
The blue wire is still available at the decoder and can be used if re-
quired, but when used on aforementioned bulbs that get power directly from the track (usually through
the frame) they must first be isolated from the power source!
MX621N, MX622N - plugs directly into the 6-pin interface (NEM 651):
Many N, HOe, HOm as well as some HO engines have this socket installed with the required mini-
mum space of 14 x 9 mm to accept the decoder.
ATTENTION:
Plug the decoder into the socket with the pins down and the
microprocessor on top
(visible)!
Index
Speaker
Speaker
F0, front
F0, rear
Train Bus Data
Train Bus Clock
Aux 4
Hall 2
Hall 3
Hall 1
Vcc
Aux 3
Aux 2
Aux 1
Common pos.
Motor 3
Motor 2
Motor 1
Ground
Left rail
Right rail
12
22
1
2
3
4
5
6
7
17
18
19
20
13
14
15
16
8
9
10
11
21
Motor (orange)
Motor (gray)
Rail (red)
Rail (black)
Lfront (white)
Lrear (yellow)
Power (blue)
Motor (gray)
Motor (orange)
Rail (red)
Rail (black)
Front headlight (white)
Rear headlight (yellow)
Common positive (blue)
