Review of IMO iSmart

Table of contents

RoadTest: IMO iSmart

Author: billabott

Creation date:

Evaluation Type: Independent Products

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?: na

What were the biggest problems encountered?: pending further testing

Detailed Review:

Phase 1: Good News can be found on Page 52 of the IMO iSmart Intelligent Relay Operations Manual (AC90Dd01).  A USB data cable is NOT required to program the device using Ladder Diagram methods.  It is really quite amazing how the software engineers figured out a way to accomplish this using such a small display screen and so few buttons.

Phase 2:  I set my initial practical application goal to enable variable control of the temperature of a 60 watt soldering iron.  I am awaiting delivery of Type K Thermocouple.  I already have some 24V Relays.  I decided to make an attempt to programming the iSmart SMT-CD-R20 using SMT Vers. 3.33  ladder diagram utility on a desktop PC.  Even though the number of options and the manner of control causes confusion, upon reading the Training Manual  (0DC6Cd01)  the required info was extracted for my simple practical application.  The basic comparison is made of an analog input (range 0-10V).  When the input, G01, is less than the target value, this PLC program  enables T03, a 4 second delay timer (internal RTC).  T03 then enables output Q1 which will turn on the Relay to apply 120V AC to the heating element in the soldering iron.  Once the target value is arrived at G01 will turn off.  T03 detects that change but remains on for an additiional 4 seconds. Q1 changes to off when T03 goes to off.

As the iron begins to cool, G01 will detect that the temperature is below the target and enable the T03 once again which will apply power to the heater and raise the temp slightly above the target. 



Phase 3:  Additional goal is to connect the wiper of a Potentiometer to G02 and use that value to define the target temp as shown in the image below.


Phase 4: 

(19 July 2012) Now for the Bad News:    Still waiting for the slow boat from China to arrive with K-Type Thermistor(s). 

And the Good News:  Analog Devices was willing to provide some samples of their ICs for processing the thermistor output.  It is called a AD8495CRMZ.  Many thanks to for that.  Looks like it might do the job all by itself but I am preparing to throw in an additional op-amp  stage just in case it is needed.   Also they have a versitile version that includes an ADC and pins to send I2C serial data packets into your 'Duino or other MPC, like, oh, I don't know, maybe the Freescale/element14 Freedom Board.  On the iSmart the ADC is inboard, so I did not require that feature. 


Conclusion:  Pending.  But, I like the ease of use of the iSmart SMT-CD-R20.

Post Script:  Some may be wondering why not let G01/G02 control Q1 directly.  An excellent question.  It was a choice to respect the limits on the switching cycle of the input and output of the Relay that Q1 will be turning on and off.  Just didn't want to hear it buzzing; may be over kill but that is my reasoning.

  • An iSmart version that will have USB capability will be really cool and useful.  Be sure to let us know if  there will be upgrade w/exchange program.  image


    From my research, it appears that the iSmart is a direct descendant of the GE Durus line of PLCs.  Would you care to expand upon the details of the iSmart's genealogy?


    Historical Trivia:  What a blessing it was and is the following: That a humble 7 segment LED  display could, without any hardware changes, represent the numeric characters 0 thru 9 AND ALSO the chosen hexadecimal characters A, b, C, d, E, and F.   One might say it was pre-ordained. 

  • Hello, I do have good news, as we are set to release an iSmart version that will have USB capability. It is in testing now, and so far everything looks good for a release on the new software / firmware release. Thanks for trying the iSmart out. Please feel free to email me any questions or applications at:



    Jason Hannah

    IMO Precision Controls