MXi005U OPERATIONS AND MAINTENANCE
Figure 4 Remote Command Inputs
2.3.2 Remote Telemetry Outputs
There are only four remote telemetries available to the operator, these being RF forward power, RF reflected power,
AGC voltage and Cutback voltage. In the table of remote signals, all remote commands have a RT_ prefix.
The only further note on the telemetry outputs concern the AGC and Cutback telemetry levels. These levels are
normally sent to the PreAmp attenuator and range from 0V to about 10V. The circuit that generates these
telemetries for the remote interface only has a range of 0V to 5V and so the values of these two telemetries are
actually half of their true value. That is an AGC telemetry reading of 2.3V actually represents an AGC voltage
level to the PreAmp attenuator of 4.6V.
All telemetry outputs of the transmitter are designed to operate between zero and +5V, referenced to ground.
Where possible and practical, factory calibration is standardised on 100% normal power or 100% normal voltage as
applicable, and adjusted to d4V to the appropriate telemetry output. All come from op-amps that can supply
only a few mA. A ground reference pin is provided at pin 12 to ease the interface task since all these remote
commands are active low and require a short to ground.
Figure 5 Remote Telemetry Outputs
2.3.3 Remote Status Outputs
There are only two remote statuses available to the operator, these being transmitter ON and an Error status. In the
table of remote signals, all remote status have a RS_ prefix.
The transmitter ON status is a relay contact that with one side of the contact connected to ground. When the
transmitter is in the ON state, this relay closes providing a path to ground to the RS_TXON signal. Thus when this
status sinks current to ground, it indicates that the transmitter is ON.
The transmitter Error status is also an active low current sink to ground, but is implemented with the output transistor
of an opto-isolator as shown in the diagram below. When the transistor sinks current to ground, it indicates that there
is some fault condition with the transmitter. This fault is an indication to the operator that there is some problem with
the transmitter (such as a VSWR trip, Interlock open or Power supply problem) that needs some attention. A ground
reference pin is provided at pin 12 to ease the interface task since all these remote commands are active low and
require a short to ground.
The Error status is a current sinking open collector output that comes directly from the NPN transistor outputs of the
opto-isolator devices. The available output sink current is dependent on the opto-isolator transfer ratio. Generally,
one can expect at least 20mA of sinking current for each output listed here. Because these are open collector, they
PUB06-76 Rev 2 July 18, 2007
06-76-5
MXi005U Operations and Maintenance
