EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: ce_lab on May 06, 2018, 07:42:26 pm
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I am hoping someone might know the values for the C1 and C2 calibration resistors used to calibrate temperature on the PACE MBT 250 stations and others. From online pictures, C1 is 100 ohms type RN60E but not sure about C2. These connect between P3-P6 when prompted by the calibration routine. Anyone have them and will to share the values?
p/n 6993-0133-P1
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Hi!
There's a clue in the MBT Service Manual!
https://www.paceworldwide.com/sites/default/files/MBT%20250%20Service%20Manual_0.pdf (https://www.paceworldwide.com/sites/default/files/MBT%20250%20Service%20Manual_0.pdf)
Pins J1-4 is annotated "CH1 RTD" and Pin J1-5 annotated "RTD Return" - the fact that it's known that one of the calibration Modules is a 100.0R resistor indicates the lower cal. set point for the microprocessor is "0.0C", and also identifies the "C-1" and "C-2" calibration resistors as connecting between "RTD" and "RTD RTN" per channel, so with this info to hand, plough thro' the service manual, and make a note of the max. temperature the unit is designed to work to, which is 482.0C., so by reference to an RTD PT100 Comparison chart:-
http://electrolyseur.fr/ZIP/Pt100.pdf (http://electrolyseur.fr/ZIP/Pt100.pdf)
. . .we read "482C" as about 274.8R, which you can make up with 1 x 240R, 1 x 33R and 1 x 1R8, all in series - you should be able to get these in 1% E24 series!
The C-1 and C-2 calibration plugs are simple 6-pin DIN connectors - RS, Mouser or Digi-key should have something that matches the plugs on one of your Pace Handpieces you can use to make them from!
Obviously if there's anyone got a pukka C-2 then this is what you need, but it you get really stuck and the value I suggest for calibration at 482C doesn't work or the Pace micro doesn't accept it (recognised by an error indication or the unit "hanging" at the "C-2" stage, then try again, but this time, try using a "C-2" value of 400.0C or 500.0C from the PT100 chart in turn until the micro accepts the figure and completes the cal!
Hope this helps until someone can read off a pukka OEM "C-2" plug for us!
Chris Williams
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Hi Chris. Yes, Pt100 and with RN60E (these look like Dale) they would likely use a standard decade value. I could narrow it down with a trimmer and see what passes... but still hoping someone might have one laying around. Thanks! :-+
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We can use another way to confirm the temp, connect the heater, and also connect a stand RES, it is should be displayed stand team same as the PT100 table.
If the temp can match the table, Just ignore the CAL
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Has anyone been able to inspect and measure the C-2 board?
Regards,
Bruce Hunter