Filter
Top Products
MDTM-8907N page 1 of 4
MDTM-8907N
Revised 10-07
Section 10
(00-02-0165)
Description
Murphy's model MDTM89 is an electronic, dual-temperature moni-
tor. It monitors two thermocouples, displays the temperature of the
thermocouple selected, and has adjustable trip points for each input.
A toggle switch provides for selection of the thermocouple to be dis-
played and/or the temperature trip point to be checked/adjusted. If
either trip point is reached, the associated output “turns on” and can
be used as a control signal, or to initiate alarms and/or shutdown.
Specifications
Power Requirements (Operating Voltages):
MDTM89-A: 100 to 350
††
VDC, CD ignition, negative
ground (FET outputs).
MDTM89-B: 100 to 350
††
VDC, CD ignition, negative or
positive ground (SCR outputs).
MDTM89-C: 12 to 24
†
VDC, negative ground, 15 milliwatts
(FET outputs).
MDTM89-D: 120 VAC (MDTM89-C with 120 V isolation module #IT-1)
(FET outputs.) Model NOT approved by CSA or Factory Mutual.
Power Consumption: CD ignition: 350 µa @ 100V;
120 VAC: 0.6 watts; 24 VDC: 0.5 watts.
Outputs: Model B: output turns on above trip point; output turns off
when power is switched off; two (2) isolated SCR outputs, 0.5 amp
@ 250 VDC.
Models A, C and D: output turns on above trip point; output turns off
below trip point; two (2) isolated FET outputs, 0.5 amp @ 250 VDC.
Ambient Cold Junction Compensation Range:
32 to 122°F (1°C from 0 to 50°C).
Operating Temperature: -4 to 158°F (-20 to 70°C).
Storage Temperature: -40 to 300°F (-40 to 150°C).
Case: Die cast aluminum.
Reset Differential: FET models: Decreases 3 Degrees (°F or °C).
SCR model: turn input power off to reset.
Measurement Range: Monitor Range 0-1999°F or °C (specify “F” or
“C” in part number).
Accuracy: With J-type thermocouple: from 150-1200°F (66°-649°C)
±1.5% of reading. With K-type thermocouple: from 400-2000°F
(204-1076°C) ±1.5% of reading. At calibration temperature.
Laboratory Approvals: CSA
†
and Factory Mutual
††
approved for
Class I, Division 2, Group D, hazardous locations).
Thermocouple Lead Length: 150 ohm lead resistance affects moni-
tor accuracy less than 1°.
Trip Point Accuracy: ±3°F (±2°C) of reading.
Trip Point Adjustment Range: 0-1999 Degrees.
MDTM89 Interface Capabilities
Model Power Source Rating
LCDT CD Ign., 120 VAC, 12/24 VDC Cl.I, Div.1, Gr.D, Haz. areas
*
S1400 120 VAC or 12/24 VDC Cl.I, Div.1, Gr.D, Haz. areas
*
MARK II and IV CD Ignition, pos. or neg. grnd Cl.I, Div.2, Gr.D, Haz. areas
**
TATTLETALE
®
CD Ign., 120 VAC, 12/24 VDC Non-Hazardous areas
*
An isolation barrier is needed between the MDTM89 and an Annunciator rated for
Class I, Division 1, Group D, Hazardous Areas.
**
When used with approved ignition. Contact Murphy for details.
†
When used with approved ignitions or 12-24 VDC. Contact Murphy for details.
††
Approved for CD ignition, 80–250 VDC.
Instructions for Installation and Operation
Model Series MDTM89,
Dual Temperature SWICHGAGE
®
Please read the following information before installing. A visual inspection before mounting for any damage during shipping is
recommended. General information and installation instructions are intended for all MDTM89 Series models.
GENERAL INFORMATION
WARNING
BEFORE BEGINNING INSTALLATION OF THIS MURPHY PRODUCT
✔✔
Disconnect all electrical power to the machine.
✔✔
Make sure the machine cannot operate during installation.
✔✔
Follow all safety warnings of the machine manufacturer.
✔✔
Read and follow all installation instructions.
†
††