Thermo Fisher Scientific Alpha TDS 200 - Manual (Page 22)

18
P2.2: Set relay as high or low set point
Select low set point to activate Relay when measured value undershoots Set point;
select high set point to activate Relay when measured value overshoots Set point.
Using both SP1 and SP2, you can select lo/lo, lo/hi, hi/lo or hi/hi set points.
1.
Key in password “022” as per procedure in Section 5.
2. Press ▲key until screen displays P2.0 and SP2. Press ENTER twice.
3. The screen will scroll P2.2, SP2, and LOW or HIGH (Default is HIGH).
4. Press the ▲or ▼keys to toggle between LOW and HIGH.
5. Press ENTER to confirm and continue to step 3 of P2.3, or press ▲and ▼keys
together to return to P2.0. Press ▲and ▼keys together to return to TDS
measurement mode.
P2.3: Set Hysteresis value
Hysteresis prevents rapid contact switching if measured value is fluctuating near the set
point. Once activated, relay will not de-activate until measured value reaches set point
plus hysteresis value.
Example: High set point is 1800.0 ppm and hysteresis 100.0 ppm, relay will activate
when value is above 1800.0 ppm, but will not de-activate till measured TDS value drops
below 1700.0 ppm.
Default hysteresis value is 5% of full scale. The hysteresis window can be set to any
value within the range 0 to 10% of full scale as shown below:
1.
Key in password “022” as per procedure in Section 5.
2. The screen will scroll P2.0 and SP2. Press ENTER three times.
3. The screen will scroll P2.3, HYS2, and current hysteresis value.
4. Press ▲or ▼keys to adjust hysteresis value.
5. Press ENTER to confirm. Press ▲and ▼keys together to return to P2.0. Press
▲and ▼keys together again to return to TDS measurement mode.