Microtel Series 500 - Manual (Page 67)

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MCS 500 Analog Channel Setup and Calibration Example
An analog channel needs the ZERO and SPAN first. Since this is a 4 to 20 mA input
channel you first need to know what value your transducer is reading at 4mA and at
20mA. Your transducer or its documentation should give you this information.
ZERO is the value represented at 4mA input into the channel.
SPAN is the difference of the value represented at 20mA - ZERO.
For example:
A water tower has a pressure transducer at the bottom of the tank. The tank is
30 feet deep. The 4-20mA pressure transducer is rated for 0 to 40 feet deep.
The sensor is suspended 5 feet from the bottom of the tank.
THE TANK IS 30 FEET DEEP
THE ACTUAL WATER LEVEL
SENSOR IS 5 FEET FROM THE BOTTOM OF THE TANK
(ALSO THE “ZERO” POINT)
Given the above information program the MCS 500 as follows:
ZERO 0500 (Program to 500 instead of 5 to get more accuracy as explained below).
SPAN 04000 (The difference of the min and max reading of the sensor - entry must be
less than 32000).
Now that you have the ZERO and SPAN programmed the next step is to adjust the
decimal place in the reading. Use the NEXT and PREVIOUS keys to select the
DECIMAL field. DECIMAL controls where the decimal point will be shown in the actual
reading, or VALUE.
Program the MCS 500 DECIMAL field to 2. (This divides the number by 100
establishing 2 places behind the decimal point.) Now reading will vary from 5.00 to
30.00 feet. Since the tank is only 30 feet deep the highest reading will be 30.00 feet
even though the sensor could be used in a forty foot tank.