TDXM-DC

The TDXM-DC’s design features a 7-character, 7-segment Liquid Crystal Display window with 1/2 in. (13 mm), easy-to-read characters. Also located on the faceplate are membrane keys for easy configuring. Highly reliable and versatile, the TDXM-DC accepts up to 24 type J or K grounded or ungrounded thermocouples. Each channel has three adjustable set points SP1, SP2 and SP3. The SP1, SP2 and SP3 set points correspond to the SP1, SP2 and SP3 outputs. Additionally, it has the selectable feature to monitor and alarm or shut down on deviation from an average for up to two groups of temperatures (GRP/DEV; deviation from average). One group could be exhaust temperatures, and another group could be bearing temperatures.

The TDXM-DC is capable of communicating with controllers, PLCs, computers or SCADA (Supervisory Control & Data Acquisition) systems by a built-in RS485 serial communications port.

The TDXM-DC is available for 10 – 32 VDC systems.

User Interface (Faceplate)
The User Interface includes a numeric LCD and a five-button membrane keypad for readout and channel configuration. Thermocouple types can be selected and set points entered through a series of setup menus.

Thermocouple Types
Each of the 24 channels on the TDXM-DC can be configured as either J or K type thermocouples and temperature units can be selected as °F or °C readout for each channel. Unused channels can be set to Ignore and will not be seen in the display and will not cause fault trips.

Control Options
Each TDXM-DC features three outputs: two Field Effect Transistor (FET) outputs and one Form-C Relay output. Each channel has three set points; one for each output. This allows for greater system flexibility by grouping sets of channels through one output.

Set Point History
The TDXM-DC stores the last set point trip for each output in non-volatile memory. For instance, if SP1 of channel 1 was the last SP1 tripped, the LCD display will read: SP1 1 when the set point history is accessed for SP1.

Sensor Inputs and Terminals
The TDXM-DC accepts up to 24 either J or K type grounded or ungrounded^* thermocouples using 24 pairs of screw-type connections. Each pair has a jumper from the factory. Any tripped set point is detected within two seconds after the set point is exceeded.

RS485 Serial Port
The RS485 serial port (Modbus RTU client) on the back of the module is provided for communicating with microcontrollers, PCs, PLCs and SCADA systems. It is recommended that a termination resistor (customer supplied) be used when the TDXM-DC is the last device connected in a daisy-chain configuration. The baud rate, number of stop bits and  server node number can be set using the keypad. Communication is half-duplex. Modbus RTU function codes 3 and 6 are supported.

* We recommend the use of ungrounded thermocouples. Errors in readings with grounded thermocouples can be the result of differences in grounding between different devices.