Analytical Technology A15 Spezifikationen PDF herunterladen (Seite 32)

ATI A15/66 Residual Sulfite Monitor

O&M Manual

Rev-W (8/10)

ANALOG OUTPUT

A programmable isolated analog output signal is provided for interface with recorders, data

loggers, or controllers. The analog output may be programmed for either 0-20 mA or 4-20 mA output.

This output signal will be linearly proportional to the measured sulfite concentration, and may be scaled

over ranges of 0-0.1 to 0-20.00 PPM. Also, the output may be spanned for non-zero based ranges as

well. Both the zero and full scale output values are programmable so that an output of 1-10 PPM could

be set if desired.

If a zero based voltage output is required, this can easily be accommodated by selecting a 0-20

mA output and placing a shunt resistor across the output. For instance, a 50 ohm resistor will convert the

output to 0-1 VDC while a 250 ohm resistor will provide 0-5 VDC. This will allow the output to

accommodate systems with zero based voltage inputs.

Programming the analog output is done in the CONFIGURATION menu as described in items 11,

12 and 13 on page 24. Connection of the output is made to the terminals shown in Figure 6.

SIMULATE MODE OF OPERATION

As previously noted, A15/66 monitors contain a mode of operation called “SIM” or simulate. This

mode of operation allows the user to adjust the sulfite value manually in order to check devices wired to

either the mA output or the alarm contacts.

To enter simulate mode, press the MODE key until the main display is on the LCD. Press CAL

once and then use the UP key to change the display to SIM. Press ENTER and the display will flash

UPDATE and the display will then read “0.000 SIM A B”.

Pressing the UP arrow will increase the sulfite value on the display. The 4-20 mA output will

increase as the sulfite value increases. Any recorders or remote reading devices that are connected to

the 4-20 mA output should respond to the increasing values. You can adjust the value to any number

desired. If the value you set on the display is above an alarm setpoint, the relay for that setpoint should

activate, as should any alarm or control devices wired to that relay.

Using the simulate mode of operation can be very useful in verifying operation of control or

recording systems that use this equipment. Be sure to return the monitor to AUTO mode of operation

when all simulation work is complete.

TEMPERATURE MEASUREMENT

A temperature element is located in the overflow chamber of the reactor module to measure the

temperature of the sample after stripping. No adjustments are required for this part of the system.

However, it is important to note that the measured temperature is often quite different than the

temperature of the water at the overflow chamber below the monitor. Some sample heating or cooling

can occur in the sample handling system. The temperature measurement is used to compensate the

measurement and must reflect the stripped sample temperature. Do not try to adjust the displayed

temperature to the sample temperature at the overflow. It is not designed to provide this measurement.

There are 2 white wires coming from the sensing element that are connected to the PCB on the terminals

labeled “RTD wiring”. If disconnected make sure the jumper is in place after reassembly.

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Analytical Technology A15 Spezifikationen Seite 32