Emerson Fisher FLOBOSS 407 Instruction Manual page 31

FloBoss 407 Instruction Manual
The FloBoss 407 power supply circuitry provides supply voltages of +5, -5, and +8.5 volts. In addition,
+12/24 volts (+T) is provided for transmitter power by means of a switching regulator.
The +T voltage is used by the built-in field I/O and the plug-in I/O modules to provide power for loop-
powered instruments such as transmitters. The +T voltage depends on the setting of a jumper on the
termination board (P15 or W1--see Figure 2-1 on page 2-6). If Jumper P15 is set to 24V or if the W1
pins are not connected (factory default), then the +T voltage is 24 volts or greater (if the input power
voltage to the FloBoss 407 exceeds 24 volts, the switching regulator shuts down and the +T voltage
follows the input voltage). If Jumper P15 is set to 12V or if the W1 pins are connected (by the supplied
jumper plug), then the switching regulator no longer operates, so that the +T voltage is 12 volts,
provided the input power is 12 volts. This setting should only be used when all the I/O loops for this
FloBoss 407 require a 12-volt source.
For Revision D or later of the termination card, the +T voltage can be software-switched. This feature
allows the +T supply to be turned on or off for field devices not requiring continuous +T power. To
control the +T voltage, use the Aux Out #1 or Transmitter flag in the Configuration Software.
The FloBoss 407 termination board provides a +B voltage for the plug-in field I/O modules that require
it. For example, the discrete output (DO) relay modules can have either a 12 volt or a 24 volt coil. The
+B voltage is the same as the input voltage applied to the FloBoss 407 and the relay module used needs
to match the power supply input.
One over-current device and a soldered fuse on the termination board provide input power protection.
The over-current device protects the fuse. Another over-current device on the termination board
protects the +T outputs.
The LV START switch (Switch S1, found on Revision E or later or the termination card) allows the
FloBoss to power up under low-voltage conditions. Normally, the FloBoss will not start up below 12.5
volts; this is a cut-off feature designed to avoid draining down the power supply battery. Hold the LV
START switch down during power-up to initiate this startup. Refer to Figure 2-1 on page 2-6 to see the
location of this switch.
Three diagnostic analog inputs monitor input power voltage, +T voltage, and board temperature. These
values can be observed with the Configuration Software (as Analog Input points E1, E2, and E5) or
with the local display panel.
The on-board (built-in) field I/O channels provide two analog inputs (AIs); one of which you can
configure as a pulse input (PI). These I/O channels are suitable for use as flow inputs, including flow
measurement in the Measurement Canada version of the FloBoss 407.
Two plug-in terminal blocks provide termination for the built-in I/O channels. Jumper P4 on the
termination board provides the input type selection for the AI/PI channel. With P4 set to "PI," the
channel becomes pulse input. The pulse input can be connected as either a sourced or an isolated input.
An LED indicator (PI IND) shows when the field input to the pulse input channel is active. Refer to
Figure 2-1, Processor and Termination Boards, on page 2-6.
Rev 5/00 2-9