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<div>Hi Håkon,</div>
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<div>No, I don’t know the highest temperature for the Roadster but someone with access to the server logs might be able to tell us.</div>
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<div>The Model S is liquid cooled and Roadster air so no direct correlation.</div>
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<div>Keep up the good work!</div>
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<div><span style="font-family: 'Helvetica Neue'; font-size: medium;">Kevin Sharpe | Founder & Trustee | Zero Carbon World, a UK Registered Charity</span></div>
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<span style="font-weight:bold">From: </span>Håkon Markussen <<a href="mailto:hakon.markussen@gmail.com">hakon.markussen@gmail.com</a>><br>
<span style="font-weight:bold">Reply-To: </span>OVMS Developers <<a href="mailto:ovmsdev@lists.teslaclub.hk">ovmsdev@lists.teslaclub.hk</a>><br>
<span style="font-weight:bold">Date: </span>Monday, 13 January 2014 14:31<br>
<span style="font-weight:bold">To: </span>OVMS Developers <<a href="mailto:ovmsdev@lists.teslaclub.hk">ovmsdev@lists.teslaclub.hk</a>><br>
<span style="font-weight:bold">Subject: </span>Re: [Ovmsdev] Motor temp does not support negative numbers (car_tmotor)<br>
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<div>I was not aware of the industry standard -40C offset, so thank you (all) for good inputs.
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The "problem" is hereby addressed :)<br>
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<div>@Kevin: Can you recall the highest motor temperature ever seen on the Roadster? Do you know is Model S has the same temperature characteristics as the Roadster?<br>
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<div>Br.<br>
Håkon<br>
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<div class="gmail_quote">2014/1/13 Mastro Gippo <span dir="ltr"><<a href="mailto:gipmad@gmail.com" target="_blank">gipmad@gmail.com</a>></span><br>
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<div>Håkon, it is industry standard to apply an offset of -40C. We should do that instead of transforming it to signed, as Collin said. That would also be directly compatible to the CAN message from the twizy. Let's wait for Mark's opinion.<br>
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Regards<span class=""><font color="#888888"><br>
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<span class=""><font color="#888888">MG<br>
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<div class="gmail_quote">2014/1/13 Håkon Markussen <span dir="ltr"><<a href="mailto:hakon.markussen@gmail.com" target="_blank">hakon.markussen@gmail.com</a>></span><br>
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<div>The highest motor temperature I ever have seen on Think City is ~45 C. This is the offset for the cooling thermostat<br>
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I cannot even imagine that other EV-motors should reach a temperature near 100C? Then the cooling system have to be out of order ... or ...?<br>
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Anybody who knows the expected operation range of motor temp for Roadster, Leaf, iMiEV and Zwizy?<br>
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Think City reports temperature in 8 bits - signed.<br>
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When bit8 (msb) is set to "1" it means negative temperature, so when the motor temp actually is -1C , OVMS reports 255C. When motor temp is -11 Ovms reports 245C ,etc.<br>
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<div>I think that this problem might apply to all vehicles(?).<br>
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Mark, do you have any suggestion for solution?<br>
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Br.<span><font color="#888888"><br>
Håkon<br>
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<div class="gmail_quote">2014/1/13 Collin Kidder <span dir="ltr"><<a href="mailto:collink@kkmfg.com" target="_blank">collink@kkmfg.com</a>></span><br>
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<div dir="ltr">I don't think you'd want to do that. 127 deg C really isn't that terribly hot and -128C is extremely cold. If it is necessary to retain use of an 8 bit variable then the standard solution is to just offset the temperature stored by -40. That
way you can read -40 to 215C which is a pretty reasonable range. Unfortunately, I fear such a change would necessitate many other changes in code. It might be better to expand to a signed 16 bit integer.<br>
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<div>On Mon, Jan 13, 2014 at 7:50 AM, Håkon Markussen <span dir="ltr"><<a href="mailto:hakon.markussen@gmail.com" target="_blank">hakon.markussen@gmail.com</a>></span> wrote:<br>
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<div>Hi (Mark).<br>
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In ovms.h the motor temperature is defined as unsigned char (non-negative):<br>
extern unsigned char car_tmotor; // Tmotor<br>
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Currently the weather is cold in Norway (-15 C) and I noticed that motor temp was 244C.<br>
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<div>Is it possible to update the car_tmotor to<br>
extern signed char car_tmotor; // Tmotor<br>
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<div> in ovms.h?<br>
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<div>Best regards<span><font color="#888888"><br>
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<div>Håkon<br>
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