Address Map And Data Format; Data Format - Teledyne 7500 Instruction Manual

7. ADDRESS MAP AND DATA FORMAT

7.1 Data format

7.1.1 Transmission data format
The MODBUS protocol used in this instrument is RTU (Remote Terminal Unit) mode.
Transmitted data is "numeric value" and not ASCII code".
7.1.2 Handling of decimal point position and measurement unit
When transmitted, the calibration concentration setting, alarm's high and low limits and
measurement concentration data have no decimal point nor measurement unit.
Calculate exact values of data upon point positioning as shown below.
(a) Calibration concentration setting (register No. 40001 to 40020)
Alarm setting (register No. 40036 to 40055)
You can know the point position for each CH (channel) and each range, and unit upon
reading in the decimal point position data (register No. 31087 to 31096), and the unit data
(register No. 31067 to 31076).
The decimal point position data has a value of 0, 1, 2 or 3. You can obtain an exact value by
the following calculation.
Case 0: Calibration concentration setting data /1
Case 1: Calibration concentration setting data /10
Case 2: Calibration concentration setting data /100
Case 3: Calibration concentration setting data /1000
The unit data has a value of 0, 1, 2 or 3, that corresponds as follows.
Case 0: vol%
Case 1: ppm
Case 2: mg/m3
Case 3: g/m3
For example, if:
CH1 range-1 span calibration concentration setting (register No. 40002) = 2000,
CH1 range-1 decimal point position (register No. 31087) = 1, and
CH1 range-1 unit (register No. 31067) = 1,
the value is 200.0 ppm.
For writing-in, proceed in the reverse. To obtain 200.0 ppm, write 2000 as calibration
concentration setting.
The decimal point position and unit are unchangeable because fixed to each CH and each
range.
Teledyne Analytical Instruments
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