If you are using Amper’s Digital Aggregator to track the utilization of your equipment, the next step is to install the wires connecting the Aggregator to the appropriate digital signal. In this article, we will outline the steps to needed to properly connect to a digital signal.
Note: This article is for Digital Aggregators.
- If you are unsure about the difference between Digital and Analog Aggregators, please see our article, .Aggregator Types: Analog vs. Digital
- For information on connecting an Analog Aggregator, please see our article, .Analog Aggregator - Sensor Placement and Installation
- If using a Digital Aggregator for the Automated Cycle Count add-on, see the article, .Installation Guide: Automated Cycle Count Add-On
- Pre-Install Checklist
- Time Required
- Machine Requirements
- Skills Required
- Tools / Resources You Will Need
- Connecting to Machine DC Power
- Picking The Right Digital Signal To Monitor
- Types of Signals That Are Compatible
- Signal Selection
- Connecting The Digital Input(s)
- Next Steps
- In most cases, the actual installation takes 15-30 minutes per machine
- If there is no obvious candidate signal, additional time may be needed to identify the best available signal. This time may vary.
- Available +24/12VDC power and ground/0V connections.
- A digital control signal or sensor output that changes state during production but not during idle time. This signal must be 24/12VDC and change between high and low states only.
- If no suitable signal exists, an external sensor would be required.
- Personnel capable of determining the best signal or sensor output available that would indicate production is occurring.
- Personnel able to open up the power and/or control panels on the machine
- Personnel capable of reading machine schematics and identifying signal wires inside the machine.
Tools / Resources You Will Need
- (Included with hardware kit) Small screwdriver, wire strippers, wire
- Any tools required for opening up the appropriate machine panel
- (Recommended) A machine schematic or wiring diagram
Connecting to Machine DC Power
For the digital inputs to function properly, the device must be connected to 24VDC power. This allows the device to properly interpret the signals it measures. The power input must be connected to +24V or +12V and to ground (or 0V/common). The device consumes under 10mA via this power input and should not significantly load the system.
- Identify an available +24V (or +12V if applicable) power output on your machine. This often is best with an unused output, but it is usually okay to use an output already in use, as the device requires very low power.
- Identify a 0V ground output. This is usually different than the chassis or earth ground, and is often identified as 0V instead of ground.
- Cut two insulated wires to length and strip the ends. These should be long enough to connect the power connections to the Digital Aggregator.
- Use one of these wires to connect the +24V output you identified to the correct screwpost input on the Digital Aggregator. In the picture below, the +24V would attach on the left side. The other wire would connect the 0V ground to the right side, leaving the middle intentionally empty.
If successfully connected, the rightmost LED should be on when the machine is powered on and +24V power is available.
Picking The Right Digital Signal To Monitor
Types of Signals That Are Compatible
The Digital Inputs on the device are intended to primarily be used to sense 24VDC signals. These are the types of signals commonly used as sensor or PLC outputs, and are the most common type of digital signal. The signal requirements are as follows:
- Voltage Type: DC
- Voltage Range: 12-48VDC (higher voltages supported, but confirm with Amper first)
- Signal Behavior: Binary state (signal is either high or low)
- Input Impedance: 600k+ ohm for signals 12-24V, 100k ohm for signals 24V+
- Input Current Consumption: <40uA at 24V
The device's digital inputs will not source or sink power from a sensor or PLC output. They are intended to measure existing signals. This allows for the device to avoid loading the signal. This also makes the inputs compatible with any signal polarity (PNP or NPN).
Finally, the input only requires one wire, connected to the existing signal output. The two terminals per input are INTERNALLY CONNECTED for passthrough or termination if required.
The key criteria for selecting a good signal to use is that it must change states at least once during each production cycle while not changing states when the machine is idle. The signal can change many times during production as long as it does not do so when idle.
Some common examples of signals include the following:
- Ram control signal (press brakes)
- Former control signal (press brakes)
- Footswitch (presses, others) note that variable foot pedals are usually not compatible as they are not binary state
- Part presence signal (various)
- Proximity switch (centerless grinding, others)
- Light curtain or line beam (centerless grinding, others)
If your machine does not have a suitable signal that can represent production is ongoing, then installing an external sensor may be the best option. This would usually be a proximity switch, light curtain, or line beam sensor. If connecting a dedicated sensor directly to the Digital Aggregator, a dummy load will usually need to be added as the Digital Aggregator does not source or sink current at the input.
Finally, if your cycle times are generally over 5 minutes, please consult with your Amper representative first to make sure production will be captured as you expect.
Connecting The Digital Input(s)
Now it is time to connect the signal(s) you identified picked in the above section.
- Before proceeding, you may want to turn off or pause the machine to prevent any temporary issues during installation.
- Locate the signal in the machine's panel. It is usually easiest to use the machine's schematic to determine the code that identifies the wire in the panel. Once identified, find a place where that wire is screwed into place. This could be an input, output, or interconnect.
- Cut and strip an insulated wire long enough to reach the Digital Aggregator from the identified location.
- Carefully unscrew the existing connection far enough to be able to insert the wire you just cut. The new wire should lay on top of the existing one. Then, carefully screw the connection point firmly back into place, ensuring that it makes snug contact with the wires.
- Finally, connect the other end of the wire you cut to one of the inputs on the Digital Aggregator. You can connect to either of the two screwpost inputs for that input number—they are internally connected to allow for pass-through or termination if required. Do NOT connect the other input terminal directly to ground or power.
- If using a sensor that isn't connected to a PLC or other load, you must connect an additional load to ensure signal changes are captured properly. When using a PNP type sensor (active high), the load should be connected between the second screwpost on the input and the 0V screwpost. When using an NPN type sensor (active low), the load should be connected between the second screwpost on the input and the +24V/+12V screwpost. Usually, a passive resistor of 5.1k ohm will work for the load, but consult the manual for your sensor to make sure it is within range.
If successfully connected, once the machine is on and running, you should see the LED corresponding to the digital input turn on when the signal voltage is high, and turn off when the signal is low.
Once you have connected the signals and verified all of your devices (both Analog & Digital) are connected, you are ready to send the installation information over to Amper. Please see our article
Digital Aggregators are not available for self-configuration. For machines using a Digital Aggregator, please submit the form below to your Customer Success Manager with the machine name, Gateway and Digital Aggregator IDs.