Liquid Controls
Sponsler, Inc.
IT400 Remote Totalizer & Rate Indicator
Page: 10
DOC#:
MN-IT400-R2c.doc
Given a flow rate of 25gpm, the current loop reading will be 6.667mA. The output
engineering units are the same as for the rate display.
Note:
For loop powered operation, refer to the
Power
section.
Note:
The
IT400
requires 7VDC of the loop supply.
•
Pulse output
is an open collector design. A pull up resistor is required for interface with most
systems. An output pulse occurs with each increment of the totalizer if a pulse output divider of
1 has been programmed. For programmed pulse divider values other than 1 the output pulse
will occur at the divided value. Functions for a frequency output, pulse width, and pulse output
divider are programmable. When the frequency output is not selected, pulses are output in
bursts at each refresh.
Example:
The totalizer increments 15 pulses (over the last refresh time) and the pulse
output divider is 5. The number of output pulses that will be generated will be 3.
Note:
If the output pulse width programmed exceeds the time required to output the proper
number of output pulses an will be displayed in the left-most character of the total display.
The
IT400
will output as many pulses as time permits at the programmed pulse width.
Example:
At a maximum flow of 900gpm the proper number of output pulses is 15 per
second, but the pulse width is programmed to 100ms and the pulse divider to 1. The 15
pulses would take 1.5 seconds (15x100ms); only 10 pulses would be outputted. Either
the pulse width must be reduced or if acceptable the divider increased.
Guideline:
calculate the maximum output pulse width:
Maximum pulse width = 1/(output pulses per second/output pulse divider)
Using the example above: 1/(15/1) = 66.6ms is maximum pulse width.
•
Alarm output
is an open collector output that can be used to externally indicate the presence
of several out of range conditions. These conditions include: temperature, flow rate, and
battery level. The ranges of temperature and flow rate are edited in their respective sections of
the
Menu
system. The Battery low level is factory set. Any Alarm condition of the enabled
alarms will activate the alarm output. Identical to the output pulse, a pull up resistor is required
to interface with most systems.
•
RS-232 interface
allows calculated values of the unit to be viewed upon request. To use this
interface, a serial device (computer or datalogger) is used to poll the
IT400
by sending one of
the listed letters (the letter by itself) to the serial port. No carriage return is necessary. The
IT400
will reply with the requested data and a CR+LF. The BAUD rate is fixed at 9600 baud
8N1. Currently, the datalogger data can only be captured via the RS-232 port. The functions
available on this interface are:
R – Rate
Z – Reset Totalizer
K – K Factor
T – Total
Q – Total CF
L – Linearizer Table
G – Grand total
W – Rate CF
F – Process Temperature (Deg F)
C – Capture Data (Trigger a datalogger event)
Note:
Using the RS-232 interface when loop powered will cause errors in the loop reading.
