This part of the package is commonly known as the transmitter. Ultimately, as electronics have miniaturized, more computation functions have been added to this mix, giving rise to the multivariable transmitter. In these devices, inputs could be acted on by using algorithms and preprogrammed functions to directly output computed variables. Although standard devices are moderately priced compared to similar industrial devices, multivariable transmitters remain relatively expensive. However, a multivariable device can replace several units, reduce process penetrations and wiring requirements, hold down costs associated with installation and commissioning, and provide easy migration to alternate fieldbus technologies, if plant expansion or modernization make it necessary.
Many multivariable transmitters are remotely rerangeable and provide remote diagnostics capability.
Tweaking process conditions Technology often evolves at the behest of its users. Smart pressure transmitters moved a step up the diagnostic ladder by letting the control engineer know remotely if a sensor was functioning or not. However, a handheld device is not required to configure the transmitter. Ability to configure sensors on site can be a real benefit in process situations where a technician s assessment of changing, but difficult to quantify, process conditions is the key to successful product throughput. Technicians set process conditions within each digester depending on the waste mix added at the beginning of the cycle.