Jon Klima, Owner
360 Trout Lane, PO Box 23, Guffey, CO 80820
Phone: 719 479-2281,  Email:
In business for 39 years


• Article 18 - June, 1996


Programmable Differential Temperature Controllers©


This is the fifth in a series of several articles that will summarize the programming capabilities of most of the differential temperature controllers used in the Colorado area. This article will summarize the Independent Energy DM-30 and DLX-30. Although the DM-30 doesn't include control capabilities, it is still useful to cover its programming capabilities simply because of the number of monitors in the field and the scarceness of programming information.


The DLX-30 and DM-30 can be used as stand alone units or in combination with the Independent Energy SP-30 series and CM-30 controllers. Independent Energy also says other equipment interfacing is possible. I would also like to point out here that if a failure should occur in the PLX-30 or DM-30 when interfacing with the SP-30 or CM-30 controllers, the failure can appear to be in the SP-30 or CM-30. Before condemning the SP-30 or CM-30, disconnect the DLX-30 or DM-30 and checkout the SP-30 or CM-30. Often times you will find the SP-30 and CM-30 will operate fine. The DLX-30 and DM-30 can monitor up to six 10 K ohm sensors. The DLX-30 and DM-30 are programmed with both the keyboard and the internally located DIP switches. The DLX-30 control functions consist of a TIMER OUTPUT (up to three ON/OFF cycles per day via dry single pole double throw relay contacts) and one temperature SET POINT output (via dry single pole double throw relay contacts). The TIMER OUTPUT functions are programmed from the A, B, and C ON/OFF keyboard functions. The temperature SET POINT output is ON whenever the T6 sensor input is equal to, or greater than the T5 sensor input. The T5 sensor input can be either a fixed set point, as selected by the T5 adjust knob and enabled by the internal B1 and B2 DIP switches or a 10 K ohm sensor connected to the T5 sensor input contacts on the sensor terminal board. The T5/T6 turn OFF differential is set at the factory to 3° F but is also programmable via the internal Al and A2 DIP switches to 5°, 10°, or 20° F. Both TIMER ON and SET POINT Output functions, when ON, are shown as indicators on the display as a 3 or 4, respectively, on the bottom row. Both DM-30 and DLX-30 have the ability to display the highest and lowest temperatures at the T6 sensor location and are cleared via the front keypad. The internal DIP switch programming also needs to be set up for your specific system job and configuration. Switch Al and A2 (not used with the DM-30) control the Output 4 OFF differential discussed above. A3 selects the display of the temperatures, of or °C. A4 is not used. A5 (not used with the DM-30) determines whether the accumulated ON time and the OFF-TO-ON transitions count of the temperature SET POINT function are reset manually or automatically at 12 a.m. A6 selects the line frequency being used, i.e., 50 or 60 Hz (use 60 Hz in this country). A7 and A8 are set to indicate to the unit how it is to be used, i.e., as a stand alone unit, with a CM-30, or with an SP-30. The C1-C4 switch settings are also dependent upon the A7 and A8 settings. Cl-C4 should all be in the ON position if the unit is used as a stand alone unit. When used with the SP-30 or CM-30, C1-C4 should be in the OFF position. The B1-B4 DIP switches are used only with the DLX-30. B1 and B2 disable the T5 adjustment knob (so an external sensor could be used) or select one of two possible temperature adjustment ranges. If the DLX-30 is used with an SP-30, you can use the DLX-30 for a remote set point of the SP-30 with the B3 and B4 DIP switches and the T1 adjustment knob.


When programming the DLX-30 or DM-30, consult their respective application manuals for details. A paper should also be enclosed within the units that details these DIP switch settings. If you need a copy of this sheet, contact me as noted below and I'll get a copy to you.


I've taken all of the above information from the manufacturer's product literature which I assume to be correct. If I've made a mistake or have left out some important information, or you otherwise take exception to what I have written, please write to me (c/o CoSEIA or to my address listed in the CoSEIA membership directory) and we will include your comments in the next newsletter.


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