HF scientific MicroTSCM Streaming Current Monitor - Manual (Page 21)

MICROTSCM (07/09) Page 17
REV 2.4
Convert the effected change in SCU to a percentage. Since the instrument always operates
in a range of +10 SCU to -10 SCU, the range is 20 SCU.
% effect = Effect X 100
Range 1
Then calculate the proportion band or PB.
PB = % Effect X 100
% Cause 1
In our example calculating the Proportional Band or P. Band with a 10% change (cause):
% effect = 0.5 SCU X 100 = 2.5%
20.0 SCU 1
PB = 2.5% X 100 = 25%
10% 1
To prevent overshoot, it is desirable to slow the control loop down a little more. To do this
the PB is multiplied by 1.5.
In our example:
PB = 25% X 1.5
≈ 38%
Once the control parameters are set into the analyzer and the dosing pump has been set,
the SP may need to be adjusted to account for seasonal change, but other than routine
maintenance and monitoring, no other adjustments should be required.
7.3.2 Entering the Control Parameters
The next step is to enter the control parameters into the MicroTSCM analyzer. To do this,
follow the steps:
1. Press /Menu to enter the Main Menu screen.
2. Press F1 (Sensor Setup) to enter the Sensor Setup screen.
3. Press F4 (Extended Setup) to enter the Extended Setup screen.
4. Press F2 (PID Analyzer) to enter the PID Analyzer screen.
5. At F1 (Mode) toggle the highlighted setting to AUTO using the STbuttons.
6. Press F3 (Set Point) adjust the Set Point (from section 7.1) using the STbuttons.
7. Press F4 (P. BAND) adjust value using the STbuttons (in our example 38.00).
8. Press F4 again (INT. TIME) adjust value using the STbuttons (in our example 100).
9. Press /Menu four times to return to the graphic monitoring screen.
7.3.3 Manual Control
To operate the system in manual mode, follow the steps 1-4 above, on step 5 use the
STbuttons to adjust the setting to MANUAL. Select F2 and a new setting called
MANUAL OVERRIDE will show. Adjust the value using the STbuttons. A +10 will
increase the pump speed by 10% and -10 will decrease pump speed by 10%. Please note
that the speed change may not be representative of dosing rate.