Economic Implications
 
 

The belief that a radio telemetry system is cheap to install is a myth. These systems are by no means cheap and justification to install a system should be weighed up against the installation of a hardwire alternative. If, and only if, hardwire is not an option should radio be considered. Examples where wire is just not an alternative is where signals are required across a busy highway where the costs of laying a cable would be exorbitant. Other examples would be the linking of a reservoir and pump house which could be separated by many miles, laying such a cable would be exceedingly costly. Further examples are the linking of a moving device, e.g. a crane, with a controller where cables would prove costly in maintenance as they would be broken on a regular basis.

This phase of the exercise involves researching equipment capable of relaying the signals within the defined requirements as determined in the section "Technical Implications". Here one can rely heavily on salesmen and technical advisors of equipment suppliers to deliver the relevant data i.e. let others do all the leg work. It must be remembered it remains your responsibility to keep the original requirement in focus and matching it to the horde of technical specifications that reach your desk. Don't be swayed by sales talk.

Costs to be borne in mind with a radio system are antennas, masts, possible repeaters, licence fees (including the effort required to obtain a licence), and peripheral radio equipment.

Setup time is another factor increasing the costs as not only does the actual process control equipment require configuring but also the radio telemetry equipment and the man hours must be added to the total requirement. In large systems it may take many months to achieve full operational status, something often not conveyed by salesmen of such systems.

It is not all doom and gloom though. Modern radio telemetry modules are extremely complex devices and an enormant amount of process control and signal conditioning, previously done by PLCs, can now be done by these devices. This means that with the correct choice of radio telemetry equipment the costs that would have been laid out on signal conditioning equipment can be diverted to the radio telemetry system which will effectively "kill two birds with one stone" (the sort of things accountants like to hear).

It is well worth mentioning that the old saying "penny wise, pound foolish" plays a huge part in costing out a radio telemetry system. There are from the unbelievably cheap to the extortionately expensive - it is your function to ensure you get value for money. Pointers in this area are not just the costs of equipment itself but the type of backup service and range of spares that will need to be carried.

Really "yes" to radio ?  >>