© 2020 All rights reserved. Data subject to change without notice.
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Rev. B | 2020.11
LPT-M - Operation Manual
To ensure robust data communications, a daisy chain wiring confi guration must be used. This
means, four wires run from one end of the digital network to the other, through the same
connections along the entire run. From one digital device to the next digital device, A goes to A; B
goes to B; GND goes to GND; 24V goes to 24V. Each CETCI digital device has t
wo RS‐485 terminal
blocks to make wiring easier. Use one terminal block for incoming wires and the other for outgoing
wires. It does not matter which RS‐485 terminal block is used for incoming or outgoing wires, just
make sure the four incoming wires are wired to one terminal block and the four outgoing to the
other terminal block. Do not mix up the individual wires or the two groups of four wires.
NOTE: WARRANTY VOID IF SOLID-CORE WIRE IS USED AT THE WIRING TERMINAL STRIP.
When using solid core wiring for distribution (in the conduit), use stranded wire pigtails 18 AWG
within the enclosure to connect to the circuit board. The rigidity of solid-core wire can pull a
soldered terminal strip complet
ely off a circuit board and this will not be covered under warranty.
An end of line jumper must be installed at both ends of the digital network. To terminate, you must
place a 120 ohm resistor on the IN (or sometimes labelled EN) termination jumper position ON the
TERM jumper bank on the FIRST DIGITAL DEVICE (which might not be the Controller) and the LAST
DIGITAL DEVICE in the wire run. The termination resistor jumper on all other digital devices in the
network should be in the disabled position. Every CETCI digital device has a termination resistor
jumper. The factory default setting of the termination resistor on all digital devices disabled.
5.7.1 Power & Output Connections
If the LPT-M is being connected to either a QCC or FCS the supply voltage will either be supplied by
the QCC or FCS and any additional power requirements of the system will be supplied by RPS-24VDC
Remote Power Supply devices. If the LPT-M is being used on systems other than a QCC or FCS
then either 24 VDC power supplies or 24 VAC Class 2 Transformers need to be used. In all cases the
voltage supply to the LPT-M should never drop below 18 VDC or 20 VAC.
