yes -we have a case where installation cost is equal to hardware cost.
By going to radio we could knock this back to less than 20%!.
The current consumption issue can be reduced by putting things to
sleep for a while - depending on application.

The Nordic chips also seem to be a good compromise between performance
& cost, but are a single sourced solutiion, as opposed to ZigBee,
which is at least "supposed" to conform to a standard.

RP



On 02/06/05, Chen Xiao Fan <xiaofan@sg.pepperl-fuchs.com> wrote:
> In the industrial automation sector, cabling is one of the
> large portion of the cost. Therefore comes the idea of fieldbus.
> Instead of one to one cable connection (each sensor to PLC/DCS),
> you will have multi-sensors connected to a bus (eg. ASi bus --
> actuator sensor interface), then through a gateway (eg: ASi
> to Profibus gateway), all the sensors are connected to the
> PLC/DCS.
> 
> Now comes the wireless, you cut the last "mile" of cable from
> the system. The problem with Zigbee is still the with current
> consumption and cost. Adding 10s of mA to a sensor which only
> consume less than 100mA is a lot. Adding US$5 to a US$25 sensor
> is as well quite a lot. The space is another issue even though
> PCB antenna is getting smaller. Another obstacle is that this
> sector is quite conservative. The PLC/DCS makers control the
> market (Siemens, ABB, Honeywell, Rockwell, Invensys, Yokagawa,
> Omron, AB, etc).
> 
> Chipcon seems to be the leader now. Parts from Freescale are
> now very expensive.
> 
> Regards,
> Xiaofan

>

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