Are you using the right wireless technology?
Using of wireless is useful in situations where wiring is difficult or costly (installation on high ceiling, at places where power source is far away, across buildings, past critical infrastructure that can’t be removed etc). The cost of using wireless can be drastically lower than using wired connection in many cases.
However, not many will realize that utilizing different types of wireless technology can further reduce the cost! For example, for long distance communications (e.g. from Singapore to overseas), the go to technology today, without any second thoughts, is to use cellular routers. The router itself will have substantial cost, but the recurring cost can add up to a huge sum as well.
It is inevitable to use cellular router for applications that requires high speed such as video transmission & real time monitoring of parameters with high sampling rate over long distances. However, over short distance or for low speed, other technologies should be considered which will help to lower cost further.
Let us take a look at 2 scenarios where cost can be saved:
1) Using of cellular router for remote monitoring of 1-2 sensors (temperature, contact etc) for more than 20km
Few wireless technologies can reach more than 20km. Wireless that can usually have base stations deployed to propagate the signals. The most popular will be cellular because every one of us today owns a mobile phone that taps on this network. It is little wonder then that cellular is often the first wireless that comes to mind when it comes to long distance.
A data sim card plan in Singapore often starts from 1gb and cost around $10 per month. This translate to $600 over a typical project life span of 5 years, just on sim card alone.
NB-IoT, caters for such applications. The hardware is about 20-30% cheaper, it consumes a lot less power than cellular modems and most importantly, the data plan cost will be closer to $60 than $600 which is a 90% in savings! This savings is substantial, considering such applications usually involves many sites.
2) Using of WiFi to monitor many sensors in a large plant.
Another popular wireless technology is WiFi, again, because we are so used to it in our daily lives. Unfortunately, WiFi just does not perform well across long distances. Have you had the frustration of not being able to receive WiFi Signal in your bedroom when your WiFi router is in the living room? The difficulty in planning for Wifi coverage is present in industries as well!
As a result, repeaters will often be used or more access points will be added. It really doesn’t make sense to implement wireless if the access point needs to connect to WAN via a backhaul of fibre/Ethernet as the backhaul is still expensive to install. Repeaters slow down the speed greatly. Perhaps most importantly, repeaters and access points that needs to be placed 20-30m apart adds up to hardware cost quickly. Moreover, when there is wireless fault, maintenance crew will have to check the hardware one by one to isolate the fault. This is extremely costly.
Furthermore, most Ethernet device does not readily cater for I/O connections or serial connections (think D-Link/Tp-Link). Hence, remote I/O that converts serial and I/O into Ethernet will have to be purchased, further adding to the cost.
A more practical solution will be to use ZigBee (large plant, line of sight) or LoRa (large plant, line of sight issues). These are designed for serial and IO transmission over long distance. For example, ZigBee can reach 1km with line of sight and allows for the creation of wireless mesh network to extend the distance. LoRa can reach 3km with line of sight, even without line of sight, it can reach 1km rather easily; 1km is a really long distance with regards to factory size! In summary, advantages are:
1) Wireless module close to sensors, hence, wireless communications fault can be isolated quickly (minimize repeaters)
2) No need for additional IO/serial to Ethernet converter or remote IO
3) Long distance coverage.
Is your plant looking to collect more data in a cost effective manner? Contact us and we will be glad to help!