Hydrastep 2468CB and 2468CD Manual | 2468CB & 2468CD Dual Power Supply Version |
2.5.1.4Configuring the Unit to Detect Electrode Error
WARNING Mains voltages are present in this instrument when power is connected.
1.Disconnect the power supply. Gain access to the input PCB by opening the cover and removing the option board.
2.Check split pads SP6 & SP7 on the input PCB are open circuit and clean (this is the default setting).
3.To change the electrode error threshold value or to disable the feature, bridge the split pads SP6 or SP7 with solder as shown in the table above.
Repeat the procedure used in configuring the first input board to set up the remaining input board as required. This concludes the configuration on the input boards.
WARNING Bridging SP7 will disable the electrode fault alarm. In this condition, a fouled electrode in water will not be detected. This is of particular importance when electrodes are used for low level alarm or cut off.
By bridging split pad 6 on the input board, the conductivity fault detection level will be increased from 104μS (normal) to 300μS (high). This may be sufficient in some cases, but not all.
Factory modifications are available to further increase this level to 800μS, 1600μS or
2000μS. At each of these stages, the measuring sensitivity of the Hydrastep system is reduced, so the most appropriate level should be chosen, not the highest. Contact your local representative for further details.
Note that input boards that have been modified are marked with the number 24680229A and the conductivity level that is acceptable.
Offset voltages:
When an offset voltage is present on the return signal and is relatively high compared to the ac voltage, it may have the effect of lifting the square wave to the water/steam switching point.
This will cause one, or more, electrodes to flash rapidly on the display as the detection circuits alternate between steam and water. When combined with the problem described above, the display becomes very confusing.
Input adapter boards (24680523A) are available which fit into the electrode cable connectors on the input board (see inset picture, right). These have series capacitors in the return side of the cables, blocking any dc offset voltages.
The electrode cable then plugs into the Input Adapter Board instead of the electrode cable connector.
1.Input Adapter Board.
2.Input Board (Partial Top View).
3.Adapter plugged into electrode cable connector (Horizontal View).
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