Appendix F: TWC Switch Codes

The format of switch codes is as follows:

<Group><Control><Inrush voltage><Inrush time><Holding voltage><Holding time>

Group

Determines the type of device that should react to a broadcast stop commands. Possible values are:

• 3: Non-irrigation device

• 4: Pump

• 5: Valve

Control

Determines the range of the holding voltage. Possible values are:

• 9: Low range

• B: High range

This is normally set to 9.

Inrush voltage

Determines the voltage during inrush, when devices are started. Possible values are in a range from 2-9, A-F and 0-1 as listed in the table below. 2 is the lowest and 1 is the highest value. This is normally set to F.

Inrush time

Determines the duration of the inrush pulse, measured in chunks of 10 milliseconds, so 3 equals 30ms, 4 is 40ms etc. Possible values range from 3-9 and A-F, where A-F corresponds to 10-15, so A is 100ms, B is 110ms and the maximum is F, which means 150ms. This is normally set to 3. If your valves won't get pulled open, try increasing the value.

Holding voltage

Determines the holding voltage. This is the current that must be applied after the inrush. Possible values are in a range from 2-9, A-F and 0-1 as listed in the table below. 2 is the lowest and 1 is the highest value. This is normally set to 5. If your valves keep shutting off, try increasing this.

Note: Increasing the holding voltage "takes voltage from the rest of the system" and you may end up reducing the capacity of simultaneously running valves.

Holding time

This is always set to 0.

The table below shows the minimum holding voltage on the decoder output at a two-wire line voltage input of 25V (normally 35V). The output will increase when the two-wire voltage increase. If voltage exceeds 27V the output voltage will be adjusted to avoid unnecessary power usage.