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Setting TEC power limit in 2510

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cvaldivia
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Joined: February 8th, 2011, 10:21 am
Country: Canada

Setting TEC power limit in 2510

Post by cvaldivia » February 8th, 2011, 10:41 am

I have been unable to determine how to set a power limit using our Keithley 2510. We have a TEC that is capable of operating up to 3A, 9.2V, and 9.2W. Of course, I can set each of the current and voltage limits without problem, but if both were reached simulataneously, this would grossly excede the maximum power.

For the moment, I have set the current limit low (1A) so that the power limit will not be exceeded; but now the 2510 does not go anywhere near the voltage limit (maxes out around 3.5V), and hence supplies only about a 1/3 of the max power of the TEC. This in itself isn't a show-stopping problem, but the fact that it limits the usable temperature range is a show-stopper. This means I can only raise the temperature by < 40 C above ambient even though the reported delta-T of the TEC is 90 C. (This is with no other thermal load to the system.) A worse problem occurs if I max out the current limit and instead reduce the voltage limit to prevent an overload in power.

Unfortunately I cannot see where to set the power limit, and have not found this in the manual, which would be a better way than reducing either the voltage or current limits. The datasheet explicitly states that the power limit *can* be set, but if you can tell me how, it would be most helpful. Cheers.

Dale C
Keithley Applications
Keithley Applications
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Re: Setting TEC power limit in 2510

Post by Dale C » February 8th, 2011, 12:58 pm

You just set the individual voltage and current limits - depending on the mode the Peltier
is operating in it will reach one limit before it hits the other and will be prevented from
going any further. There is no direct "power limit" setting - just enter what the manufacturer
recommends for the voltage and current limits and it should work just fine.

The flaw in just multiplying the max voltage by the max current is that the Peltier will never
operate in that "corner" of the acceptable voltage and current limits at the same time.

cvaldivia
Posts: 2
Joined: February 8th, 2011, 10:21 am
Country: Canada

Re: Setting TEC power limit in 2510

Post by cvaldivia » February 9th, 2011, 6:23 am

I've just run some measurements on our setup with the limits set as you suggested for the current and voltage. Unfortunately, the device does reach very near the "corner" of the operating range, as I observed a power usage going up to 24 W, which is well above the manufacturer's specified 9.2 W maximum. There must be some way to prevent this issue, and I don't understand why this is an issue for me but not for everyone else who has used the 2510.

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