LTMT Main Unit

The LTMT main unit is the main module of the TeSys Tera system which co-ordinates with different modules to provide features like protection, control, monitor, data storage, communication, and so on.

The LTMT main unit is available with following communication protocols:

Modbus RTU
PROFIBUS DP

The advantages of the LTMT main unit are:

The LTMT main unit provides power to the LTMTCT/LTMTCTV sensor module and LTMT expansion units.
The LTMT main unit is independent of LTMTCT/LTMTCTV sensor module type. The LTMT main unit can be used for current-based protection or current and voltage-based protections.
The LTMT main unit can be mounted on top of the LTMTCT/LTMTCTV sensor module, which reduces width of basic module.

Except communication interface, all the LTMT main unit connections remain same in all variants.

For more information on TeSys Tera installation, refer to TeSys Tera Motor Management System Installation Guide – DOCA0356EN.

Front Face Description

NOTE: Please contact your local Schneider Electric representative concerning its availability of the EtherNet/IP variant.

A	Digital input connectors
B	RJ45 port for expansion unit connection
C	RJ45 port for HMI connection
D	Modbus or PROFIBUS DP connector
E	Temperature input connector
F	Power supply connector
G	Reset button
H	Status LED
I	Digital output connectors

Status LED

LED name	Status	Description
Device	OFF	Power OFF
	Green ON	LTMT main unit is in healthy condition (turned ON after power ON self-test).
	Green blinking	LTMT main unit is in logic test mode.
	Red ON	Internal error detected or configuration error detected.
	Red blinking	Communication between LTMT main unit and LTMTCT/LTMTCTV sensor module or LTMT expansion units is lost.
Motor Status	OFF	Motor in Inhibit state.
	Green ON	Motor in Stop state, ready to Start.
	Green blinking	Motor is running.
Trip/Alarm	OFF	No trip or alarm condition.
	Blue blinking	Alarm condition is present.
	Blue ON	Pickup condition is present.
	Red blinking	LTMT main unit has tripped and trip condition is still present. Trip cannot be reset.
	Red ON	LTMT main unit has tripped and trip condition is not present. Trip can be reset.
Communication	OFF	Communication is not established with PLC or DCS.
	Green ON	Communication is established with PLC or DCS.
	Red blinking	Communication is lost with PLC or DCS.

Trip/Reset Button

Use the Reset button to perform the following functions:

Function	Description	Procedure
Trip reset	Resets all trips that can be reset.	Press the button and release it within 3 s.
Self test	Performs a self test if: No trips exist Test mode function is enabled.	Press and hold the button for more than 3 s not exceeding 15 s.
Return to default values	Returns the LTMT main unit parameters to default values if the motor is in Stop state. If the motor is in Start or Run state, the return to default values is ignored.	Press and hold the button for more than 15 s not exceeding 20 s. When the button is pressed for more than 15 s, the Trip/Alarm LED blinks in blue color. The controller parameters are reset to their default values when the button is released.
Induce a trip	Put the LTMT main unit into internal trip condition.	Press and hold the button for more than 20 s. The LTMT main unit trips and trip is recorded in the Trips log.

Digital Inputs

The LTMT main unit has four potential free digital inputs (type 1 according to EN61131-2 standard).

The digital inputs can be powered through either of the following ways:

Internally by the LTMT main unit.
By an external power supply. The input supply voltage is 24 Vdc ± 15%.

When the digital inputs are powered internally, the four digital inputs I.1, I.2, I.3, and I.4 can be used.

When the digital inputs are powered by an external 24 Vdc power supply, only the three digital inputs I.1, I.2, and I.4 can be used. The digital input I.3 is connected to the external power supply.

Digital Outputs

WARNING
UNIntended equipment operation When motor is running with starter: Under nominal condition: Digital output of LTMT main unit and expansion unit will remain in NC state and follows the DO input source. Under degraded condition: If LTMT main unit and expansion unit cable will disconnect, the digital output of LTMT main unit will be in NO state, and the digital output of expansion unit will be in NC state. Failure to follow these instructions can result in death, serious injury, or equipment damage.

WARNING

UNIntended equipment operation

When motor is running with starter:

Under nominal condition: Digital output of LTMT main unit and expansion unit will remain in NC state and follows the DO input source.
Under degraded condition: If LTMT main unit and expansion unit cable will disconnect, the digital output of LTMT main unit will be in NO state, and the digital output of expansion unit will be in NC state.

Failure to follow these instructions can result in death, serious injury, or equipment damage.

The LTMT main unit has three digital outputs:

Two outputs with NO contacts
One output with NO+NC contacts

LTMT Main Unit Temperature

One 2-wire PT100 or PTC temperature sensor can be connected to the LTMT main unit.

Expansion Port

The expansion port is used to connect optional LTMT expansion units with the LTMT main unit. All expansion units are connected in daisy chain.

NOTE: Please contact your local Schneider Electric representative concerning its availability of the EtherNet/IP variant.

LTMT HMI Port

The LTMT HMI port is used to connect the optional LTMTCUF control operator unit with the LTMT main unit. For more information on cables, refer Cables section.

The pinout of the shielded RJ45 connector of the LTMT HMI port is as follows:

Pin No.	Signal	Description
1	–	Not connected
2	–	Not connected
3	–	Not connected
4	D1 or D(B)	Transceiver terminal 1
5	D0 or D(A)	Transceiver terminal 0
6	–	Not connected
7	+5V	Auxiliary supply to LTMTCUF control operator unit
8	0VL	Signal and power supply common