FW Murphy TDXM-DC Series, Installation And Operation Manual

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Section 10 00-02-0511
2019-07-10 1
General Information
Description
The innovative TDXM-DC gives you a unique, configurable temperature scanner/pyrometer with a built-in power
supply. The design features a 7-character, 7-segment Liquid Crystal Display window with 1/2 inch (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 (3) 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 from 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 systems by a built-in RS485
serial communications port. The TDXM-DC is available for 10 - 32 VDC systems.
User Interface
The User Interface includes a numeric LCD display and a 5-button membrane keypad for readout and channel
configuration. Thermocouple types can be selected and set points entered through a series of set-up menus. See
Setup Menu in Set Up section.
Thermocouple Types
Each of the 24 channels on the TDXM-DC can be configured as J or K type thermocouples, and temperature
units can be selected as °F or °C for the readout of each channel. Unused channels can be set to
Ignore and will
not be seen in the display and will not affect the outputs. All the unused channels must have the jumper installed.
Control Options
Each TDXM-DC model features three outputs: Two outputs are the Field Effect Transistor (FET), and one output
is the Form-C Relay. Each channel has three set points, one for each of the outputs. This allows for greater
system flexibility by grouping sets of channels through one output.
Setpoint History
The TDXM-DC stores the last setpoint 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 in the Setpoint History for SP1.
Pressing the channel SP1-3 key will show the channel and the setpoint for that channel. If the trip was from a
group function, the offending channel is shown with the value of the deviation from average.
Sensor Inputs and Terminals
The TDXM-DC accepts up to 24 type J or K grounded or ungrounded* thermocouples using 24 pairs of screw
type connections. Each pair has a jumper from the factory. Any tripped setpoint is detected within two seconds
after the set point is exceeded.
RS485 Serial Port
The RS485 serial port (MODBUS RTU slave) on the back of the module is provided for communicating with
microcontrollers, PCs, PLCs and SCADA systems (see Typical Wiring Diagrams). 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 slave node number can be set using the keypad.
Communication is half-duplex. Modbus RTU function codes 3 and 6 are supported. Devices on the RS-485
network must have a common ground.
Modbus Integer Holding Registers
See TDXM-DC I/O Addresses.
Replacement Parts
Plug, kit, TDXM-DC: Terminal Plug replacement kit-P/N 10-00-7848
* We recommend the use of ungrounded thermocouples. Errors in readings with grounded thermocouples can
be the result of differences in grounding between different devices.