Hardwired Sensors and Plug-in Cables

Analog sensors measure a range of values and the most commonly used analog sensor is one that monitors for temperature ranges from low to high or extreme temperatures. Analog sensors connect to the analog port on an environment monitor.

The term digital sensor is generally applied in engineering to a device that monitors a binary output i.e. 1 or 0, ON or Off. The term ‘digital sensor’ in environment monitoring can also refer to an ‘intelligent’ sensor that monitors data within a range of specific values. This term is commonly used with Avtech Room Alert devices. Avtech digital sensors include temperature and temperature/humidity monitoring sensors. When either of these are plugged into a compatible environment monitor, the temperature or temperature/humidity data is automatically logged for analysis.

Digital sensors and Analog sensors are two types of sensor that can be used in environment monitoring. A digital sensor monitor a state, being ‘On’ or ‘Off’ i.e. 1 or 0. An Analog sensor monitors provides a continuous or intermittent (sampled) data stream for analysis. Example of an analog sensor is a temperature or temperature/humidity sensor. An example of a digital sensor would be Power Sensor which is signalling whether a power supply is on or not. A typical analog data sensor is a temperature probe.

A switch sensor uses relays that are either Normally Open (NO) or Normally Closed (NC) and can only be on one of these two states. The states can be used to indicate normal running and alarm conditions. When the set condition being monitored changes, the switch sensor changes from NO to NC or NC to NO. The opening or closing of the relay determines whether a voltage is present and it is this that an environment monitoring device monitors and records or uses to invoke an action in a detector i.e. a Smoke Alarm, Air Flow, Fuel Tank level or Water level monitor.

An actuator is a device that responds to a digital input or output and moves. It is a control mechanism for a system that responds to a signal to indicate the need for a change in state such as a valve to open or circuit breaker to be opened.

A 1-Wire sensor is a sensor using the 1-Wire device communications bus. This provides a low-speed data signal and power using a single conductor. 1-Wire is typically used to communicate with small devices like digital thermometers and measurement devices. When a 1-Wire sensor is connected to an environment monitor, the system can be termed a ‘MicroLAN’. The term ‘1-Wire UNI’ is used to refer to sensors other than for temperature or humidity.

A NIST Sensor has a traceable calibration certificate to standards set by the National Institute of Standards and Technology (NIST). AKCP offer certified sensors in two formats:

Calibrated Sensors (AKCP suffix -NIST2)

A 2 NIST certified, temperature sensor has a built-in calibration check. Each temperature sensing unit has 2x NIST calibrated and certified temperature sensors (acting as a pair). The primary sensor value is checked by the secondary sensor, and if the detected range is greater than the stated accuracy, an alert is generated that the sensor is out of calibration. This makes ACKP NIST2 sensors ideal for monitoring environments requiring a high degree of monitoring data accuracy and a calibration check.

Calibration Checked Sensors with Failover Function (AKCP suffix -NIST3)

3 NIST certified, calibrated temperature sensors are compared once a second for accuracy, with a backup, if the sensor is out of calibration. An AKCP NIST3 sensor has a built-in calibration check with calibrated sensors working in 3 pairs. The primary sensor value is checked by the secondary sensor, and if the detected range is greater than the stated accuracy, an alert is generated that the sensor is out of calibration. The sensor will then automatically failover to the next pair and continue monitoring with a seamless graph of data. AKCP NIST3 sensors are ideal for environments requiring a high accuracy, calibrated sensor with failover backup to ensure continuous monitoring of the critical environment.

The National Institute of Standards and Technology (NIST)

NIST stands for the National Institute of Standards and Technology and a US physical science laboratory, and part of the US Department of Commerce. From smart electric power grids and electronic health records to atomic clocks, advanced nanomaterials and computer chips, many products and services rely in some way on the technology, measurement and standards provided by the National Institute of Standards and Technology. More information: https://www.nist.gov/

Virtual Sensors can be a very powerful tool in your sensorProbe+ environmental monitoring system. Each sensorProbe+ comes with a number of free virtual sensors and additional virtual sensor packs can be purchased as required.
Virtual sensors can be configured for:

• Boolean
• SNMP Get
• Virtual Ping
• Logic
• SNMP Trap Receiver
• Modbus

Virtual Sensor Example

SNMP Get, sensor logic evaluation and ping commands amongst others are all possible using virtual sensors. For example, you could use a sensorProbe+ SP2+ as a probe manager. If you had a SP2+ and multiple sensorProbe devices they could all be monitored, mapped and alerted via the SP2+ device. You can perform SNMP Get commands on a server to monitor memory or CPU load, or you can ping network enabled devices and be alerted if they go offline. Please note: The Virtual Sensor Ping cannot ping an IP address on the VPN network. We’ll explain more about the Virtual Sensors and how to configure them in the Notifications manual.

AKCP Virtual Sensor Configurations

• Boolean: works on the Virtual Sensor by checking the status of, for example 2 to 3 sensors and if the sensors status matches that of the setting, they will return a value of 1.The normal value is 0.
• SNMP Get: with the SNMP Get sensor, you can get a value from any SNMP device. Note that a custom string return value is not supported.
• Virtual Ping: with the Ping sensor, you can set up ping monitoring of a network device or server.
• Logic: the logic Virtual Sensor type uses FlipFlop logic. You can monitor physical sensor statuses with it, and change the Virtual Sensor’s state with the pre-set values for the status of a physical sensor (SET Source Sensor). The logic will ignore all other intermediate physical sensor statuses and only changes the Virtual Sensor’s state back if it exactly matches the specified physical sensor status (RESET SourceSensor) .
• SNMP Trap Receiver: the SNMPTrap Receiver type will check 3 parameters before setting a value for the virtual sensor. These three parameters are the IP Address, the sensor OID and the Trap sub-type.
• Modbus: use a Virtual Sensor (up to 60, 4 devices and 15 sensors on each) to monitor via ModBus using a sensorProbe+ on RS-232, RS-422, RS-485, Ethernet and other communications network protocols. sensorProbe+ supports RS-485 and Ethernet. The Modbus/RTU protocol defines how a ‘master’ device polls one or more ‘slave’ devices to read and write data in real time over RS-232, RS-422, or RS-485 serial data communication. A slave device cannot volunteer information; it must wait to be asked for it. The master will write data to a slave device’s registers, and read data from a slave device’s registers. A register address or register reference is always in the context of the slave‟s registers. Modbus/TCP, an extension of Modbus/RTU, defines how Modbus/RTU and Modbus/ASCII messages are encoded within and transported over TCP/IP-based networks. Modbus/TCP is just as simple to implement and flexible to apply as the original Modbus/RTU. The sensorProbe+ can represent both “master” and “slave” devices and supports both Modbus RTU and Modbus TCP protocols. For example, use the AKCP Power Monitoring Sensor (PMS) to monitor the power related information including Phase Line Voltages, Phase Line Current, Watts, Power Factor and Kwatt or Kilowatt hours. You can also upload a configuration file to use a 3rd party PMS in the PMS UI.

Please ask for a copy of a PDF of the sensorProbe+ Notifications Manual if you need more information on how to setup Virtual Sensors for your device.