truAPM | Advanced Panel Meters by truAPM

Frequently Asked Questions

Quickly find the answers you need by using the quick links below:

VOLT METER (APM-VOLT-XXX)

How do I switch the VOLT meter between AC and DC voltages?

You do not need to. The APM continually looks at the input and if it sees an AC voltage (both positive and negative voltages) it will automatically switch into AC mode and will calculate and display the true RMS voltage. If no positive and negative voltages are detected then the APM will assume that the input is DC and will display the average voltage.

Will the VOLT meter measure noisy AC Voltages?

Answer: Yes. The APM samples the voltage input at a rate of 62KHz. The samples then go through a digital low-pass filter before being displayed. The low pass filter allows frequencies below about 5KHz to pass through but block higher frequencies.

Will the VOLT meter measure AC voltages produced by an SRC or Triac?

Answer: Yes. From firmware revision 6, the APM will calculate and display the true RMS voltage – even if the waveform is non-sinusoidal and/or asymmetric.

What’s the accuracy and resolution of the VOLT model? Your data sheet states an accuracy of 1% but it does not define whether this is 1% of the input signal or 1% of the range.

To maximize accuracy the VOLT meter incorporates a programmable gain amplifier (PGA). This amplifier acts rather like an iris and automatically opens and closes depending on the input voltage. The PGA has 16 different ranges as shown below (click to view large).

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As an example, with a 110V input the APM will be on range 12 and the resolution will be 81.6mV. The worst case error will be 1.6V.

AMP METER (APM-AMP-XXX)

What can I connect to the APM-AMP model?

You can connect the APM-AMP model directly to your circuit to measure AC or DC currents up to 5A on circuits carrying less than 42V AC/DC. You can also connect a CT (current transformer) directly to the meter. You can configure the CT ratio using the DIP switches on the rear of the APM or alternatively using the APM configurator software.

Can I use a current shunt with the AMP meter?

We have developed a model specifically for use with current shunts. Please click here here for further information on our SHUNT meter.

How immune is the AMP meter to magnetic interference?

The APM-AMP meter can be affected by magnetic interference from strong magnets and conductors carrying high voltages. To ensure that these do not affect the accuracy of the meter please ensure that these are kept at least 6 inches away from the meter.

What is the difference between the APM-AMP meter and the APM-CT meter?

The APM-AMP meter is a general purpose current meter that can be used for measuring currents in a wide range of applications. The APM-CT meter has been optimised for use with external CTs. The APM-AMP model can only be used to measure AC currents using a CT and offers improved accuracy over the APM-AMP meter.

What is the nominal input impedance of the APM-AMP meter?

0.002 ohms

What CT power rating do I need for use with the APM-AMP meter?

Minimum recommended CT rating is 1VA

PROC METER (APM-PROC-XXX)

Can I measure amps and volts at the same time using a PROC meter?

No. The PROC meter has two inputs but you can only use one of them at a time. You can connect both inputs of the PROC meter to your circuit but only the selected unit will be used. The other input is ignored.

Both the PROC meter and the VOLT meter can measure voltages. What is the difference between these models?

The main difference is that the Volt meter can measure voltages up to 600V (both AC and DC) whereas the PROC meter can only measure DC voltages up to 10V.
The PROC meter is also more accurate than the VOLT meter and supports non-linear conversion.

Both the PROC meter and the AMP meter can measure currents. What is the difference between these models?

The AMP meter can measure bi-directional current flow (-5A to +5A) with both AC and DC currents. The APM PROC meter can only measure DC uni-directional currents (0 to 50mA). The PROC meter is also more accurate than the AMP meter and supports non-linear conversion.

What is non-linear conversion

The PROC meter includes a 20 point linearization table that can be used to correct for non-linear sensors such as thermocouples and pressure transducers. This feature is accessible directly from the APM Configurator software.

CT METER (APM-CT-XXX)

What is the difference between the APM-AMP meter and the APM-CT meter?

The APM-AMP meter is a general purpose current meter that can be used for measuring currents in a wide range of applications. The APM-CT meter has been optimised for use with external CTs. The APM-AMP model can only be used to measure AC currents using a CT and offers improved accuracy over the APM-AMP meter.

What is the nominal input impedance of the APM-AMP meter?

0.002 ohms

What CT power rating do I need for use with the APM-AMP meter?

Minimum recommended CT rating is 1VA

MODEL OPTIONS

What are the various models of the APM?

We are constantly developing new models so the list keeps on growing. To view our current range please go to www.truAPM.com. If you have a specific application and cannot find the perfect meter then please click here to contact your local sales team to discuss your requirements further.

Can I change a volt meter to a current or frequency meter with the software?

No – please make sure you purchase the correct model for your application.

I cannot find a model that meets my specific requirement

Please contact our technical support team. They are always happy to help. Please click here for their contact details.

What is the difference between Output and No Output models

The only difference is that Output models have two physical outputs. These can be configured to be either digital (open collector) or analogue. No Output models do not have these outputs.
Both Output and No Output models have alarms that can be configured to change the backlight and message when the input signal is on or out of range.

DISPLAY

What is the difference between positive and negative display?

The positive LCD has black digits and a bright background. The digits are readable in bright sunlight. The digits are readable with the backlight on or off.
The negative LCD has bright digits and a black background. The display offers the highest contrast when used in-doors. The digits are only readable when the backlight is on.

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Can a positive APM be changed into a negative APM?

No – Each model is factory built with either a positive LCD or a negative LCD and the LCD cannot be changed in the field.

Can the backlight be configured to come on and go off automatically?

You can configure the backlight colour as well as when it’s on, off and flashing using the APM Configurator software. You can configure the backlight be:
– Be on and only go off when a specific condition is met, or
– Be on and flash when a specific condition is met, or
– Be on and change colour when a specific condition is met, or
– Be off and only come on when a specific condition is met, or
– Be off and flash on when a specific condition is met.

Can the APM display a center “0” on the bar graph?

Yes. For example, to show a bar graph that goes from -10 to +10 you need to:

a) Under Display Rage select ‘Fixed’
b) set ‘min‘ to -10
c) set ‘max’ to +10

Once downloaded to the APM the bar graph will go from -10 to +10 with a center zero

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How visible is the APM in sunlight?

This depends on the LCD that you have chosen. Positive LCDs are very readable in direct sunlight, but you will not be able to see the backlight colour (the sun is so much brighter than any LEDs we can get our hands on!). Negative LCD are readable outdoors but not in direct sunlight.

Can I use a 24vac power to this device and still use the outputs?

Yes but you must only connect APMs to the AC supply. Also remember to connect the COM terminal on the APM to the same 0V/GND as your output.

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How much power does the APM require

Each APM will consumes 1.6W worst case. This assumes that the backlight is on full intensity and both analogue outputs are sourcing 20mA. The table below shows the maximum current required at various PSU voltages:

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Can I power multiple APMs from a single supply?

Yes you can. When using a DC supply, just makes sure that the power supply you use is rated sufficiently to power all the APMS. Each APM draws a maximum of 1.6W.
In the special case of using an AC supply and an APM with outputs you can connect multiple APMs to the same supply but you must not connect any other device to the same AC supply.

OUTPUTS

Will the APM’s output turn on a warning light?

Yes – but please make sure you purchase a model with outputs. Depending on the voltage and power requirement of your warning light you may need some additional components (such as a relay or power transistor) to interface between the APM and your warning light.

What is the sink capability of the digital outputs

The maximum current that the APM can sink is 500mA. The APM can therefore be connected to a load of up to 12W. Please note that the maximum voltage that can connected to the outputs is 24V.

Can I output live data from the APM to view on a computer?

Yes but not directly. The USB port can only to be used to configure the APM. If you want to look at live data then you need purchase an APM with outputs and then configure one of them to ‘Analog’. The APM will then output a current in the range of 4 to 20mA that is proportional to the displayed value on the APM. If you want to view this information on a computer then you will also need to procure a 4-20mA interface for your computer.

Can the output be latched?

The APM outputs are only active when the condition is true. If you want to latch the output you need to connect a latching relay to the output of the APM. Please remember to fit a protection diode across the relay coil to prevent the back EMF from the coil damaging the APM.

How do I output 4-20mA and connect it to my PLC ?

To output 4-20mA on SP1 terminal, use the APM Configurator Software. Make sure you select the ‘Alarm 1’ tab (Alarm 1 tab controls SP1 output and Alarm 2 tab controls SP2 output). Then:
1) Select ‘Analogue Output’
2) Enter the measured voltage that you want to correspond to 4mA on the output
3) Enter the measured voltage that you want to correspond to 20mA on the output
4) Select APM – Write Configuration to APM.

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Then connect SP1 and COM to your circuit as shown below:
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Is the 4-20mA output a current sink or source?

The 4-20mA output is a current source. The output will deliver a current between 4mA and 20mA into a maximum resistance of 250 ohms. Please remember to enable “analogue output” using the APM Configurator as all outputs default to digital.

CONFIGURATION

Do I have to configure the meter or does it come pre-programmed?

Every APM comes with 15 pre-configured settings and these can be selected using the DIP switch on the rear of the APM. Please refer to your models user guide for a list of switch positions. Please click here to go to the user documentation.
Custom configurations can be created and downloaded to the APM using the freely available APM Configurator software. Please click here to download the latest version.

What are the DIP switch positions to allow auto ranging?

All APMs are shipped from the factory in auto-ranging mode. If you have changed the configuration and want to return back to auto-ranging then please make sure that all the DIP switches on the rear of the unit are pointing to the left (away from the screw terminals) as shown below. You will then need to run the APM configurator application, select ‘Auto Ranging’ and then APM  Write Configuration to APM

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Do you provide custom configurations?

Our technical support team are always happy to help. Please click here for their contact details.

What type of cord/cable should I use to connect the APM to a PC? Where can I get it from?

To connect the APM to a PC you will need a standard USB AB cable. The cable can be purchased from most electrical distributors or alternatively directly from Trumeter. The Trumeter part number for the cable is 022128-01.

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Will it work with a mini USB adaptor?

The APM has a Type B USB socket and you can use standard off the shelf adapters to convert this to a different type if you want.

Can I connect more than one APM to my computer and program them all at the same time?

You can connect multiple APMs to your computer but you can only program one of them at a time.

How does the “scale” and “offset” work in Display Scalar?

By default the display scalar is set to x1 and one unit of measure on the input equals one unit of measure on the display. As an example if you have a VOLT model and ’Display Scalar’ is set to x1 then 1 volt on the input would equal 1 volt on the display. However, in certain applications, you may want to apply a correction factor to the displayed value. As an example if you want 1 volt on the input to equal 10 volts on the display then all you need to do is select ‘User’ and enter 10 in the Scale box. Similarly if you want the displayed value to be the input value plus 3 volts then enter 3 in the Offset box. If you set both a Scale and an Offset then APM will apply the Offset first followed by the Scale. For example, applying a Scale of 0.01 and an Offset of 2 will result in:

Scaler chart small
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In the example above applying 20V to the meter the displayed value would be (20V + 2) x 0.01 = 0.22V.

Can I copy configurations from one APM to another?

Yes you can. Just connect the meter that you want to copy to your computer and run the APM Configurator software. Select APM – Read Configuration from APM. Now select File – Save Configuration File to save a copy of the configuration on your computer then disconnect the APM and close down the APM Configurator.
Now connect the meter that you want to configure and run APM Configurator. Select File – Load Configuration File to load the original configuration file and then select APM – Write Configuration to APM.

Can I save configurations?

Yes. Click on File – Save Configuration file. You can also read the configuration from an APM. Just click on APM – Read Configuration from APM.

Can I change the configuration once I have set it? Or is it “burned in”?

You can change the configuration as many times as you wish. You just need to connect the APM to your computer and download a new configuration. Downloading a new configuration will automatically overwrite the old configuration.

How many times can I change the configuration?

The configuration is stored in FLASH memory which can be reliably overwritten at least 1000 times.

How do I configure the APM-AMP meter to use my CT?

You can either use the DIP switches on the rear of the APM or you can use the APM Configurator Software.

 

    USING DIP SWITCHES:

The table below shows the various switch positions. Lines 5-16 are for use with external 5 amp CTs:

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    Using the APM configurator

To use the APM Configurator, make sure that all the DIP switches are in the OFF position (to the left pointing away from the screw terminals). Under ‘External Sensors’ select ‘CT’ and then enter the primary (input) and secondary (output) currents of your CT. In the example below the CT has an input of 300A and an output of 5A (i.e. 300:5)

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What does the “Limit Decimal Places” function do?

By default the APM will display the reading on the four digit display to maximum resolution possible by automatically moving the decimal point to the right and left as the input signal changes. In some applications this might not be desirable and hence Limit Decimal Places allows you to limit the maximum number of decimal places that the APM will display. As an example if you select ‘1 (0.0)’ then the APM will display the measured value to no more than one decimal place.

What does the “Display Peak Bar” and “Peak Hold” do?

The “Display Peak Bar” provides a visual indication of the average peak value on the bar graph display similar to what’s seen on a graphic equalizer. The duration the peak bar is visible is configurable from a few seconds to a few minutes by adjusting the ‘Peak Bar’ slider on the Response tab. Alternatively, if you want the Peak Bar to be latched on and show the maximum value since the unit was reset, click ‘Peak Hold’.

How do I reset the “Peak Hold” ?

There are two ways: either by power cycling the APM or by using an external switch connected between the COM terminal and the RST terminal on the rear of the unit.

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What does the “Display Zero” function do?

The display Zero function allows you to display zero when the input is below a specific value. This is useful in situations where there is noise around zero and you do not want to display this on the APM. As an example if you are monitoring a 600VAC circuit you may want to set Display Zero to 10 so that the meter will display 0.000 volts when the input is below 10 volts.

Can I configure an APM at my desk and do I need to connect power supply?

You can configure the APM from your desk. Just connect the APM to your computer using USB. You do not need an external power supply as the APM will draw its power from the USB port. When the APM is powered from USB it will show ‘USB’ on the display. In this mode you can upload and download new configurations to/from the APM but the APM cannot take any measurements or drive any alarms or outputs.

What is the maximum cable size for connectors?

The screw terminals can accept cables up to 3.3mm2 / 12AWG.

How to reset my APM unit?

To reset the APM disconnect power for three seconds.

How to reset my APM unit back to factory defaults?

To restore the APM back to factory defaults connect the meter to your computer and run the APM configurator. Select your meter and then select File – Load factory defaults. Then select APM – Write Configuration to APM.

How do I update the firmware?

Please click here for full instructions on how to update the firmware

What is the default backlight colour?

The default backlight colour is white. You can change the default backlight colour using the APM configurator software. The APM configurator software can be downloaded from here

Is there a cost for the programming software?

No – The APM Configurator software is free. Please click here to download the latest version.

Do I need a physical meter to view the software?

No – You can run the APM configurator without needing to connect an APM. You can open, edit and save configuration files on your machine without needing to connect an APM.

Run the APM Configurator Software. Click on ‘Configure APM’:

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A list of models should appear. If the model that you want to configure is not shown in the list then click on ‘Download All APM Models’ and the software will automatically download all models from our update server. Please note than an internet connection is required to download new models.

Click on the required model from the list and then click ‘Configure’

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I have download a configuration to the APM but it is not being recognized by the meter

To enable custom settings on the APM please make sure that all the DIP switches on the rear of the unit are pointing to the left (away from the screw terminals) as shown below:

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How do I get the unit back to the factory defaults?

Using the APM configurator select File – Load factory defaults. Then select APM – Write configuration to APM.

Will I need to get permission from my IT Manager to download the software

Please refer to your company’s IT policy.

MOUNTING AND ENVIRONMENTAL

Is the APM environmentally rated?

The APM is rated for IP65; NEMA4 and NEMA12 from the front. A sealing gasket is supplied with each APM and the APM must be installed correctly. Please follow the installation instructions carefully especially in terms of the panel cut out dimensions.

What is the size of hole that I need to create in my panel to accept the APM?

The panel cut-out needs to be 68mm x 68mm (-0mm; +0.7mm) / 2.68” x 2.68” as per DIN 43718 and IEC61554.

What is the comparable DIN size?

The APM has been designed to meet both DIN 43718 and IEC61554.

Can I use the APM outside mounted in a panel and it can survive being in the elements (Sun, Wind, Rain, Snow)?

The APM is constructed from UV resistant plastic and can operate in temperatures from -10 deg C to +60 deg C. The front of the meter is fully sealed but an additional enclosure is required to protect the rear from the elements. Care needs to be taken in the design of the enclosure to ensure that the environment inside the enclosure does not exceed 85% humidity non-condensing.

How heavy is an APM?

This varies model by model but typically is about 180g (0.4 pounds).

What holds it in a panel?

The APM is supplied with a mounting clip. The meter is first installed through the front of the panel and then the mounting clip is installed from the rear of the meter.

Is the APM CE marked?

Yes. Please click here to get a copy of the CE declaration of Conformity.

Does the APM meet the requirements of RoHS?

Yes. The APM meets all the requirements of The Restriction of Hazardous Substances Directive 2011/65/EU (RoHS 2). Please click here to get a copy of the CE declaration of Conformity.

Is the APM UL listed?

We are in the process of obtaining both UL listing for the USA and cUL listing for Canada.

What standards are the APM certified too?

All APMs are certified to IEC61010-1 and are CE marked. Please refer to the certificate of conformity for a detailed list of standards. Click here.

PRICING, ORDERING, CUSTOMIZATION AND WARRANTY

What is the cost of the APM?

Please click here to contact your local sales team to discuss your requirements further.

If purchased in bulk, does a discount apply?

Yes. Please click here to contact your local sales team to discuss your requirements further.

Can I have it with my logo on ?

We’ll always try to meet any special requirements that you might have. Please click here to contact your local sales team to discuss your requirements further. Please note that special requirements normally involve longer lead times and minimum order quantities.

Where is my nearest distributor

Please click here to contact your local sales team to discuss your requirements further.

I really like your APM but can I have one in blue?

We’ll always try to meet any special requirements that you might have. Please click here to contact your local sales team to discuss your requirements further. Please note that special requirements normally involve longer lead times and minimum order quantities.

What is the warranty period

All Trumeter products carry a three year warrantee. Please click here for further information on our warranty.

Does Trumeter normally have APMs in stock and if out of stock, what is the average lead time?

Most orders are filled within days from stock held at distributors or at Trumeter regional stocking locations. We work with all our customers to understand their requirements and stock accordingly. Orders or requirements above stock levels may require up to 12 weeks lead time.

Who is my regional sales manager and how do I get in contact with him/her?

Please click here to contact your local sales team to discuss your requirements further.

SOFTWARE

I am having trouble installing the APM configuration software or I am not able to update my device from my computer.

Please check with your IT department as you may have a firewall or anti-virus product that may be blocking the process. Please try disabling your anti-virus during the install or configure your firewall to allow access to the update server (IP address: 103.6.244.216)

Do I have to worry about checking for updates to the software?

To automatically check for updates every time that the APM Configurator is run select Updates – Automatically Download Updates.

Alternatively, to manually check for updates, select Updates – Download Updates Now.

Please note that an internet connection is required to check and download updates.

How do I update the firmware in the APM?

Click on Updates – Download Updates Now. The APM Configurator will check with the update server and notify you if an update is available.

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If there is an update Select Update – Install Updates for Selected Meter and then click on ‘Install’

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TROUBLESHOOTING

What should I do if my APM has a dark background?

First check that there is power on the PSU terminals and that it is between 12V and 24V. Next, using the APM Configurator software reset the APM back to factory defaults by connecting the meter to your computer; select your meter; select File – Load factory defaults. Then select APM – Write Configuration to APM.

The screen is blank on my APM. How do I fix it?

First check that there is power on the PSU terminals and that it is between 12V and 24V. Next, using the APM Configurator software reset the APM back to factory defaults by connecting the meter to your computer; select your meter; select File – Load factory defaults. Then select APM – Write Configuration to APM.

I have some oil contamination on my APM display screen. Any suggestion on cleaning it off?

Use a mild detergent and a soft cloth.

Do I have to worry about checking for updates to the software?

To automatically check for updates every time that the APM Configurator is run select Updates – Automatically Download Updates.

Alternatively, to manually check for updates, select Updates – Download Updates Now.

Please note that an internet connection is required to check and download updates.

How do I update the firmware in the APM?

Click on Updates – Download Updates Now. The APM Configurator will check with the update server and notify you if an update is available.

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If there is an update Select Update – Install Updates for Selected Meter and then click on ‘Install’

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