Connecting Picolog 1216 with Analog Pressure Sensor

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andycph
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Connecting Picolog 1216 with Analog Pressure Sensor

Post by andycph »

Hi,

I am trying to setup the Picolog 1216 to work with an analog pressure sensor:
www.smcpneumatics.com/PSE533-M5-CL.html

Can someone show me where and how to get started?

Thanks in advance.

Gerry
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Re: Connecting Picolog 1216 with Analog Pressure Sensor

Post by Gerry »

Hi andy,

Looking at the Series Catalog, once you've supplied it with 12 to 24V, the output of the sensor will very between 0-5V. So, to connect it to the PicoLog 1216 for capturing your pressure readings, you would need to connect it as shown on Page 3 of the 'PicoLog 1000 series Small Terminal Board Users Guide', here: https://www.picotech.com/download/manua ... -guide.pdf, with a resistor value of 10kΩ for both R1 and R2 (to divide the output down to the 0-2.5V input of the Terminal Board). The physical connections would be to the Terminal blocks for Gnd and the Channel input, and you would need to cut a link on the board for R1 (when using Ch 1) as shown on Page 6.

For the software, PicoLog 6, you would need to connect the Data Logger to the PC via USB, start the software and click on the image of the Logger. Then select '1' to open the Channel 1 settings window, set the sample interval to the value you need, click on the 'Advanced options' to open the next window, then click on the 'Probe or Scaling' text box to open the 'Probe and Custom Scaling' window. In that window, click on 'Table' and enter the following to create a scaling Table:
0 0
2.5 5
This will display the 0-5V output value of the sensor in your captured data, and completes the interfacing setup. For general operation of the software, go here: https://www.picotech.com/data-logger/pi ... 6-software ( there is also a video to take you through the software operation).

Regards,

Gerry
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andycph
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Re: Connecting Picolog 1216 with Analog Pressure Sensor

Post by andycph »

Hi Gerry,

Thanks. Appreciate the help.

Cheers,

Andy

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Re: Connecting Picolog 1216 with Analog Pressure Sensor

Post by andycph »

Hi Gerry,

Finally soldered the solid state resistors to the terminal board, on R9 & R10 and R11 and R12. This would correspond to C9 and C11 right? Decided to use C9 and C11 as C1 was too close to the edges.

I measured that the resistances were 10 kiloohm (thereabouts) across the connections.

I applied the leads from a variable voltage power supply to the C9 (and then C11), and when the voltages exceed 2.5V, I would the "out of range" warning, and I noticed that the Picoscope was measuring 1:1. Isn't the Pico supposd to measure half the voltage that is shown on the power supply?

Would appreciate if you can provide some pointers.

Gerry
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Re: Connecting Picolog 1216 with Analog Pressure Sensor

Post by Gerry »

Hi Andy,

Did you cut the links on the board as shown on Page 6 of the Small Terminal Board Users Guide?

Regards,

Gerry
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Re: Connecting Picolog 1216 with Analog Pressure Sensor

Post by andycph »

Hi Gerry,

Yes, I cut the connections for both R9 and R11, hence I was able to measure the resistances after soldering.

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Re: Connecting Picolog 1216 with Analog Pressure Sensor

Post by andycph »

Hi Gerry, I found the error. For C9, I should solder the 10kohm resistances to R17 and R18, and for C11, to R21 and R22 respectively, as shown in Figure 5 (Page 5).

Gerry
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Re: Connecting Picolog 1216 with Analog Pressure Sensor

Post by Gerry »

Hi Andy,

Sorry didn't have time to check your results before the weekend (so Just thought I'd put in a sanity check and come back).

Glad you found the error.

Regards,

Gerry
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Re: Connecting Picolog 1216 with Analog Pressure Sensor

Post by andycph »

Hi Gerry,

I have another sensor, from EFE Sensor, which is the 4-wire millivolt output type. The 4 wires are:

RED: + EXCITATION (+10 V)
GREEN: + SIGNAL (Channel 5)
WHITE: - SIGNAL (Channel 6)
BLACK: - EXCITATION (GND)
SHIELD: SENSOR HOUSING (Leave it alone? Or connect to GND?)

The datasheet stated the excitation as 10 Vdc. I therefore should supply 10V to the RED wire?
Also, my initial thoughts were to wire as shown in the brackets above, and use the Math option in Pico Data Logger to determine the differential between Channels 5 and 6. However, I am not sure about the calibration. In the datasheet, the values for Zero Balance (mV/V) and Sensitivity (mV/V) are stated. How do I enter these values into the Table?

Gerry
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Re: Connecting Picolog 1216 with Analog Pressure Sensor

Post by Gerry »

Hi Andy,

Unfortunately, it's not as straight forward as you think. With differentials you have a negative going voltage relative to the Gnd reference, and the PicoLog 1216 only measures fixed range positive voltages. Fortunately, however, the PicoLog 1216 has an internal current source, so what you can do is apply offset and scaling, using resistors on the terminal board.

In order to do that we would need to know what the differential output voltages are. I would assume that the sensor divides the 10V input into +/-5V making a common (Gnd) point at 5V. Could you confirm if that is the case?

If it is the case, then you can use the 10kΩ, and two 20kΩ resistors (as shown on page 4 of the 'Small Terminal Board User guide'), to perform the offset and Scaling.

Regarding Zero balance and sensitivity, do you mean '/bar', or '/psi', rather than '/V'?

Regards,

Gerry
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Re: Connecting Picolog 1216 with Analog Pressure Sensor

Post by andycph »

Hi Gerry,

I have contacted the customer support of the sensor company to find out. In the meantime, should I go ahead and experiment with the resistor values that you have suggested, what is the worst thing that can happen? I assume the readings will be just wrong, but it won't blow things up right?

Gerry
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Re: Connecting Picolog 1216 with Analog Pressure Sensor

Post by Gerry »

Hi Andy,

Actually, it will be better to check first. The output may be directly from a Wheatstone Bridge, in which case using the Logger to remove the Common Mode voltage would give you a significantly reduced dynamic range, while using a differential instrumentation amplifier module would not only get rid of the CM voltage but would also amplify the small signal, to maximise the full scale input range of the Logger (which you can then compensate for in your scaling file).

Regards,

Gerry
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Gerry
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Re: Connecting Picolog 1216 with Analog Pressure Sensor

Post by Gerry »

Hi Andy,

Could you send an email to support@picotech.com and mark it for my attention, as I don't have your email address and can't respond.

Regards,

Gerry
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Gerry
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Re: Connecting Picolog 1216 with Analog Pressure Sensor

Post by Gerry »

Hi Andy,

OK, disregard my last post, found your message.

Regards,

Gerry
Gerry
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