User's Manual

Product Description
2 R900 Wall and Pit MIU Installation and Maintenance Guide
Product Description
R900 MIU Programming
The MIU is NOT field programmable. At the factory, each of the following items are
programmed into the MIU:
• Serial numbers – Each MIU is given two unique serial numbers/identification
numbers (two IDs for compound units). Even numbers are given to the single
registers and odd numbers are given to a two-networked registers unit. Cus
-
tom serial numbers are not available.
• Time between encoder register reads – The MIU reads the ProRead (ARB VI)
register once an hour and E-Coder (ARB VII) registers at 15-minute intervals.
• Time between MIU transmissions – The time between MIU transmissions is set
for approximately 14 seconds for single registers, and alternates register trans
-
missions every eleven (11) seconds for two networked registers. Custom time
is not available.
RF Protocol Error Detection
The RF protocol is comprised of a header, data packet, and an error detection
mechanism that reduces the erroneous data.
RF Frequency Control Algorithm
The MIU’s frequency-hopping, spread-spectrum has a sequence of at least 50 differ-
ent channels for transmitting data. Associated with the 50 channels are 50 frequen-
cies that can be pre-selected in a pseudo random manner. These 50 frequencies are
coded into the software.
RF Transmission Period and Randomness
The random period generation uses the same random seed created for the channel
definition to generate the transmission randomness. The randomness algorithm is
defined so that no two consecutive transmissions from two MIUs will interfere
with one another.
Low Battery RF Emissions
The MIU stops RF transmissions when the battery discharges below the normal
operating voltage.
The R900 MIU avoids 914 MHz to prevent collision with the Advantage
®
probe.