YOKOGAWA TB400G-A1 Series, User Manual, Page: 63 / 140

<5. FUNCTIONS>
5-4
IM 12E04A02-02E
• When the output range is switched, digital range information is output only once (see Section 2.1, "Digital Communication
Speci fi cations").
• When the turbidimeter is used with auto-range, the output should be set as shown below.
(1) Set the Low side of the setting to 0 (display is "L00.00").
(2) Set the High side of the setting so that range 1 <= range 2 <= range 3 holds.
(3) If two ranges are required, set range 2 = range 3.
(4) If one range is required, set range 1 = range 2 = range 3.
• Range switching timing in auto-range should be taken as follows:
(1) The timing of switching from a low range to a higher range is a point where the measured value just becomes larger than the
auto-range switching point of the lower range.
(2) The timing of switching from a higher range to a lower range is a point where the measured value just becomes smaller than -10
% of the auto-range switching point in the lower range (10 % is provided for range switching hysteresis).
Note: Auto-range switching should be set in item 7. When the turbidimeter is shipped from the factory, this is set to 80 % of the range.
• In auto-range, the output ranges are switched for contact inputs (R1, R2, and R3).
(1) No contact input: Output range 1
(2) Contact input (R1, R2) = Closed: Output range 2
(3) Contact inputs (R1, R3) = Closed: Output range 3
5.2.2 Other Functions Related to Output
Table 5.3 shows other functions related to analog output and the operation modes and function
numbers for setting.
Table 5.3 Other Functions Related to Output
Detected item Details Mode FUNCTION
1) Bi-linear output
Setting of break points when an analog signal is output
with linesegment approximation.
PROGRAM 1 6
2) Output hold during
maintenance
When maintained (other than the <MEAS.> mode), the
function to hold the analog output.
PROGRAM 1 4.
3) Output mode
when a failure is
detected
Analog output mode (non-hold, hold, or preset) selection
when the "FAIL" lamp is lit.
PROGRAM 1 5.
4) Holding an output
of 4 mA or less
If a turbidity value becomes smaller than the output
range lower limit, the output is held at 4 mA (1 V).
PROGRAM 1 6.
5) Setting of output
value if a failure is
detected.
If "preset" is selected in function 3), the value set here is
output.
PROGRAM 1 5
(1) Bi-linear Output
The point where a setpoint (%) of the output range span (mg/l) corresponds to 59 % of the output
signal (4 to 20 mA or 1 to 5 V) span is the break point. The setting range is 0 to 100 %. Figure 5.2
shows an example of a setting.
F0502.ai
0 1 4
5
3 2
12
20
4
Break point
mA
Output range (mg/l, (deg.))
40 % setting
Example of setting
Output range:
0 to 5 mg/l (deg.)
Output: 4 to 20 mA
Break point setting: 40 % (2 mg/l (deg.))
Output
signal
Figure 5.2 Example of Bi-linear Output
If the output range setpoint is determined to be 50 %, the output is linear. Also, if set at 0 % or 100
%, the output is as shown in Figure 5.3 respectively.
3rd Edition : May. 31, 2010-00