This article will walk you through how to wire the I/O module for Utilization following examples of typical, or most common machine connections. Below are six examples of methods used to collect Utilization from a Machine.
Please Note: This article is part of the Digital I/O Integration process. For more details on the process as a whole, please review the Digital I/O Integration Guide
What is Utilization?
Utilization refers to the amount of time the machine is in use compared to the amount of time the machine is down. MachineMetrics typically tracks this at the machine level by tracking the percentage of time a machine is in-cycle. A machine is considered in-cycle if it is currently running a program.
What is an I/O Module?
The I/O Module is a DAQ device (Data AcQuisition) and captures an analog DC voltage at the AINx terminals.
The typical Utilization terminals are defined as follows:
Vs - This terminal supplies +5vdc and each Vs terminal is internally connected.
GND - This terminal is connected to the ground pin on the incoming USB power connector. All the GND terminals are connected and are the same as the ground line on the USB connection. This is often the same as ground on the DC power supply, which is often the same as AC mains ground.
AIN0 or AIN1 - These terminals have a usable input range of +/- 10vdc, however they are capable of handling up to +/- 40vdc. If a higher voltage input is used, such as 24vdc, then the signal will be clamped at 10vdc.
This is the most common form of collecting utilization from most machines. It requires mounting the supplied Current Transducer (or CT) around one of the three motor phases. This can be accomplished at the output of a motor starter or the VFD drive. A three-phase servo drive motor can also be monitored using this same method (although a TrueRMS current sensor should be used for this application). In general, the scaling jumper is removed to keep the AC Amps to volts DC at a 1:1 ratio.
Example 1 Machine Uses
- Band saw/Metal saw
- Drill press (single-phase connection)
- Other single motor applications
This method of collecting utilization is used to capture activity on machines that have more than one operating motor or axis, only one may be running at a time. It requires mounting the supplied Current Transducer (or CT) around one of the three motor phases on each motor. This can be accomplished at the output of motor starter or the VFD drive. A three phase servo drive motor can also be monitored using this same method (although a TrueRMS current sensor should be used for this application). In general, the scaling jumper is removed to keep the AC Amps to volts DC at a 1:1 ratio.
Example 2 Machine Uses
- Laser Tables
- Router Tables
- CNC or Lathe (with 2 spindles)
This method of collecting utilization uses a set of normally open (or closed) dry contacts from a standard relay or a PLC that has a relay card option. If using a PLC relay, the output would need to be pre-programmed with a "running" status. When the machine is active or running, the contact would close and allow 5vdc from the Vs terminal to pass through the contact to AIN0.
Example 3 Machine Uses
- Robot cells
- Conveyor lines
- Press brakes
- Folding machines
- Other machines with "running" or "in-cycle" relay with spare contact
This method of collecting utilization uses the existing PLC or processor output that turns on a green stacklight (usually indicating machine is running or is active). A single wire can be used to connect the PLC or processor output of 12-24vdc to AIN0 on the I/O module.
Example 4 Machine Uses
- Any machine that uses a green stack light and has an output that is 12-24vdc.
This method of collecting utilization requires a connection to the 24vdc Down Foot Switch circuit found on most press brakes (see example 6 for a 120vac footswitch). A connection can be made at the input terminal, or an insulation displacement T-Tap can be used to connect to the wire as shown in the example (this method is preferred if the PLC input terminal is at its capacity). A single wire is then run from the input wire to the AIN0 terminal on the I/O module.
Example 5 Machine Uses
- Press brakes
This method of collecting utilization is similar to example 5 except the control circuit is 120vac and requires a 120vac relay to be used. Once the relay is installed the A1 of the coil is wired to the PLC input and of the Down Foot Switch and the A2 of the coil is connected to neutral. The normally open contact can then be wired as shown in the example 6 diagram.
Example 6 Machine Uses
- Press brakes
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