Doepfer CTM64 Relay Board - Manual (Page 2)

The CTM Relay Board is an expansion board for the universal MIDI control electronics
CTM64. The reason for this this additional board is the limited cable length between the
CTM64 main board and the contacts (max. about 50 cm / 2 ft). By means of the relay board
the cable length can be extended to 100m/300ft and even more.
The working principle is very simple: The relay board is equipped with 16 reed relays that
can be switched via very long cables. The relay board is placed near the CTM64 main board
and the contacts inside the relays are the new contacts for the CTM64 main board. Thus the
cable length between the contacts and the CTM64 main board is less than 50cm but the
cables used to switch the relay can be much longer. For each relay a screw terminal is
available to connect a simple 2 pin cable with the controlling contact on the other side (e.g. a
momentary or toggle switch). The relay board is operated with a separate power supply to
obtain a complete galvanic separation between the relays and the CTM64 main board.
These are the most important features:
• 16 Reed relays, the contacts of the relays are used as the contacts for the CTM64 main
board
• relay connections via 2 pin screw terminals
• cable length > 100m/300ft (cables up to 100m have been tested but probably even
longer cables are possible)
• up to four CTM relay boards can be connected to one CTM64 main board
• separate power supply for the relay board(s), independent from the power supply of the
CTM64 main board. An external power supply with 7-12V DC output is required. The
current depends upon the number of relays that have to be switched actually. Each relay
consumes about 10mA. The full installation (i.e. 4 relay boards, all relays in operation)
requires a power supply with about 640 mA.
• additional screw terminal to operate several relay boards with one power supply only (if
no galvanic separation is necessary even the power supply of the CTM64 main board
can be connected to this terminal, provided that the power supply is sufficient)
• connection between each CTM relay board and the CTM64 main board via 16 pin ribbon
cable, and one single cable (common line) that leads from the CTM64 main board to all
relay boards
• the 16 pin ribbon cable is included with the relay board
• the power supply has to be ordered in addition (only one supply required, even if more
than one relay board is used), see accessories and price list on our website.
• dimensions: about 164 x 42 x 18 mm
The sketch on page 6 shows the wiring of the Relay Board(s) with the CTM64 main board
and the contacts/switches.