Sensor wiring to a SIEMENS 6es7134-6gf00-0aa1

I am doubting on how to wire an analog sensor to this SIEMENS Analog Input module:

https://support.industry.siemens.com/cs/attachments/109475183/et200sp_ai_8xi_2_4_wire_ba_manual_en-US_en-US.pdf

My sensor has the following terminals: "+" and "GND".

As you can see in the manual there are 2 possible terminals for the first channel: "1" and "9".

Which one should be connected to the "+" on my sensor. I think that should be the "9" but the plus sign on the terminal "1" name makes me doubt.

On the other hand, makes any difference if the sensor is loop powered or not loop powered.

Thanks!

What is the sensor that you are trying to connect?
Voltage or current?
4-20ma, 0-10vdc?

Regards,

It is 4-20 mA

1=+
9=gnd

I don't have any Siemens equipment to check out, but I disagree with Ozzie's statement.

If the field device is a 2 wire, loop powered transmitter, then I suspect that Siemens uses the '2 wire' term correctly for its 2 wire diagram on page 11:


But I think that L+ is probably connected to Uv terminal 9 by the path in red, shown above.

That would mean that the transmitter's + would connect to 9 and the transmitter GND would connect to terminal 1, Io+.

From terminal 1, the current is dropped across the internal resistor.

I propose:
1 = GND
9 = +

I'd test terminal 9 with a voltmeter and see if it has 24Vdc on it. Of course, there's probably some obscure setup/configuration/switches to choose between current or voltage inputs and 2 wire or 4 wire.

I am glad to see that I am not the only one having doubts with this configuration

I will try to check with a voltimeter if I have 24V on pin 9, but according to the diagram on the manual I am almost sure it will be.

The point is that I have loop powered sensors (temperature and flow) and not loop powered (valve positioner feedback). Does it make any difference in the way they should be wired to the AI module?

Thanks!

It isn't clear to me how setup/configuration/switches/base unit determine the functionality of the AI card. Terminals 1A through 8A do not even appear on the 2 wire diagram - are those associated with the light or dark base unit modules? The implication to me is that the AI card might set up for either 2 wire or 4 wire, but not both.

Assuming you can figure that out, a 4 wire device powered from the AI card would be wired as shown.



If you don't use the DC power connections on the AI card, you risk having a ground loop between the 4 wire device and the AI card, which could appear as an signal offset, signal driven offscale or damaged input card, depending on the voltage difference between the grounds.

Are you certain a positioner current output is a 4 wire output? The Siemens PS2 is a 2 wire current output.

The strange think about this SIEMENS manual is that the 4-wire diagram shows +/- polarity for the power feeding to the sensor, but no polarity on the signal, same as the 2-wire diagram: no polarity at all.

As far as I know the 2-wired loop powered sensor could be damaged if conected to the wrong polarity, right?

Are you certain a positioner current output is a 4 wire output? The Siemens PS2 is a 2 wire current output.

Click to expand...

The valve positioner is self powered so I thought that the feedback signal was not loop powered. Maybe I am wrong and the positioner is not "self-powering" the feedback signal and it should be powered by the 2-wire loop, could it be?

Strange indeed. I call it the German minimalist philosophy.

How hard is it to add Power (+), Power (-), signal (+), signal (-) to a diagram ? ? ? Unless arrogance is the working norm (I can say that because my last name is unmistakeably German). Still, Siemens is a wealth of information compared to Sick (another German company).

Many 2 wire transmitters are protected from reverse polarity with a diode. I say many, because there are too many to make a definitive statement. I know for a fact that a recently obsoleted Siemens ultrasonic clamp-on flowmeter's loop powered current output was irreparably destroyed when connected reverse polarity, even momentarily, because it happened to me. Current Honeywell Smartline 2 wire transmitters are specifically polarity insensitive, connect it either way and they'll work. It's about time, it is the 2nd decade of the 21st century. I suspect in 10 years, most 2 wire devices will migrate to polarity insensitivity for competitive reasons.

You need to check your positioner model number and its manual to see how its AO current re-transmit signal is powered; there are both 4 wire and 2 wire positioners from the same vendor.

Likewise with the positioner AO. Although Siemens PS2 AO is loop powered, it doesn't mean every one is.

are you use 2 wire or 4 wire ?

what type base unit are used?

input are + and all are mA input.

danw said:

You need to check your positioner model number and its manual to see how its AO current re-transmit signal is powered; there are both 4 wire and 2 wire positioners from the same vendor.

Likewise with the positioner AO. Although Siemens PS2 AO is loop powered, it doesn't mean every one is.

Click to expand...

You can see the positioner wiring instructions in the page 11 of the following manual:
http://www.ps-automation.com/files/download_files/OI_AMS1x_PSL_Mod4_ENG_COM_0.pdf

I think I will consider the "Active Position Feedback" signal as a 2-wire loop powered one. But in any case I am not sure yet about the right connection to the SIEMENS AI module...

gclshortt said:

What is the sensor that you are trying to connect?
Voltage or current?
4-20ma, 0-10vdc?

Click to expand...

Most of the sensors are 4-20 mA 2-wire loop powered. For instance the following temperature transmitter (page 58):
http://www2.emersonprocess.com/siteadmincenter/PM%20Rosemount%20Documents/00809-0200-4728.pdf

soyxan said:

I think I will consider the "Active Position Feedback" signal as a 2-wire loop powered one. But in any case I am not sure yet about the right connection to the SIEMENS AI module.

Click to expand...

1) The device is an actuator, not a positioner.

That actuator is line powered or DC powered.

2) The Active Position Feedback signal is powered from the actuator, hence it comes from a 4 wire device. It is not a 2-wire loop powered output. The use of the term 'active', says that the actuator powers the 4-20mA position feedback signal. The term 'passive' is used for loop powered outputs, which this is not.

The note at the bottom of the wiring terminals about galvanic isolation is there to reassure you that the isolated output is not likely to develop a ground loop with your PLC AI card.

3) If the AI card tolerates 2 wire and 4 wire connections at the same time, then the
- actuator's Active Position Feedback signal (+) is wired to an Ix+ terminal and
- the feedback signal (-) is wired to M.

On the 4 wire AI diagram, M is connected to nA terminals, 2A, 4A, 6A, 10A. But it isn't clear to me when there are A terminals and when there are not A terminals.

danw said:

1) The device is an actuator, not a positioner.

Click to expand...

You are completely right, I just said positioner as I wanted to focus on the "position feedback" signal

That actuator is line powered or DC powered.

Click to expand...

Line powered (AC)

2) The Active Position Feedback signal is powered from the actuator, hence it comes from a 4 wire device. It is not a 2-wire loop powered output. The use of the term 'active', says that the actuator powers the 4-20mA position feedback signal. The term 'passive' is used for loop powered outputs, which this is not.

Click to expand...

You mean that the actuator has an internal 240 VAC to 24 VDC converter to power the Active Position Feedback?

In any case loop powered or not loop powered, the signal is 2-wire and should be connected to the analog input module on the same terminals, right?

3) If the AI card tolerates 2 wire and 4 wire connections at the same time, then the
- actuator's Active Position Feedback signal (+) is wired to an Ix+ terminal and
- the feedback signal (-) is wired to M.

Click to expand...

The card is configured for 2-wire signals.

What I am wondering now is why not wire it as you suggested in a previous post?
UV = +
Ix = GND

Thanks a lot for your help

danw said:

1)
On the 4 wire AI diagram, M is connected to nA terminals, 2A, 4A, 6A, 10A. But it isn't clear to me when there are A terminals and when there are not A terminals.

Click to expand...

this for individual (-) cable 4W

it can tolerate 2W and 4W but the cable messy if using 2W configuration