Of the many options that can be used to control levels in Tesira, one allows the use of external potentiometers. Since potentiometers are analog devices, these need to be connected to Tesira through an EX-Logic. This note covers the details on wiring off-the-shelf potentiometers as well as Biamp’s RP-L1 and RP-L2 Remote Panels to the EX-Logic.
Wiring a generic potentiometer
Wiring a potentiometer to an EX-Logic can be a bit confusing since it has three contact points. Not wiring it properly might cause the potentiometer to either work in reverse or not at all. Looking at the pot from the knob side with the contact points pointing at you, you will have the Low or CCW (Counter Clockwise) terminal on the left, the W (Wiper) terminal in the middle and the High or CW (Clockwise) terminal on the right. Connect the CCW terminal to the Ground terminal, the W terminal to the analog input and the CW terminal to the +5V terminal of the EX-Logic as shown in the diagram below.
A linear-taper potentiometer in the 5K – 50K range is recommended. When the Tesira control voltage port calibration wizard (in Device Maintenance) is run it will sense the voltage range passed by the potentiometer. Note that if a logarithmic (audio-tapered) potentiometer is used, the control will not seem to work “evenly” across the range.
The inputs do have noise filtering but for longer cable runs, lower-value potentiometers in the 5K-10K range will have greater noise immunity.
Wiring the RP-L1 or RP-L2
The Biamp RP-L1 and RP-L2 are wall plates with 25KΩ linear taper potentiometers for volume control. The RP-L1 has only one potentiometer while the RP-L2 has two. These potentiometers came prewired from the factory with pigtails for ease of installation. These pigtails are color coded green for Low or CCW (Counter Clockwise) terminal, red for W (Wiper) terminal and white for High or CW (Clockwise) terminal. Connect the CCW (green) wire to the Ground terminal, the W (red) wire to the analog input and the CW (white) wire to the +5V terminal as shown in the diagram below.
Please note that the RP-L1 and RP-L2 products have been discontinued as of Fall 2015.
- All potentiometers that are connected to the EX-Logic must be calibrated to ensure proper operation. See the Tesira software help file for more information.
- EX-LOGIC programming