Implement temperature sensor and override on two wires of an STR-104 to a Xenta Programmable

[Product_Support]

Issue

An STR-104 can be used to monitor space temperature with a Xenta programmable controller. If a zone override is also required, the most straight-forward solution is to wire the override button to a digital input on the same controller. However, if those wires were not installed, or sufficient inputs are not available on the controller, the override button can be sent via the temperature sensor wires.

Environment

• STR-104
• Xenta programmable controllers
• Xenta 280, 281, 282, 283, 300, 301, 302, 401, 401:B

Cause

If enough wires were not run, or sufficient inputs are not available on the controller, the override button can be sent via the temperature sensor wires.

Resolution

The override signal sent via temperature sensor wires is accomplished by shorting the temperature sensor reading to ground. The Menta application senses this short and interprets it as a zone override.

1. On the STR-104, short terminals 12 to 14 (Therm to Switch)
2. On the STR-104, short terminals 11 to 15 (M to MX)
3. Terminals 11 and 12 on the STR-104 go to M and B1 on a Xenta programmable (for example).
4. Download this Menta macro for use in the programmable Menta application.

While the button is pressed, the temperature will jump to a failed-shorted value of 300+ °F.  The attached Menta app will read in this jump, filter it out from a failed sensor, and enable an override for an adjustable duration.