Vaux and Saux

[apu]

They say the only stupid question is the one you don't ask -- but I still feel a bit stupid asking. Am I correct in saying the following about the M1Gold control board?

1) The positive terminals for Vaux and Saux are at the same voltage. The only difference is that power to Saux (positive) is momentarily removed when the alarm is reset in order to reset the smoke detectors.

2) The negative terminals for Vaux and Saux are always at ground voltage, regardless of system normal, trouble, alarm, or reset.

The manual says "all negative terminals [...] are at the same reference" except the earth ground terminal (no connection) and the common terminal of Output 3. But, that statement is under the +VAUX so I'm just triple-checking that it applies to -SAUX and -VAUX even though it is in the +VAUX section.

Auxiliary Power Connections (+VAUX)
Motion detectors, glass breaks, etc. and other devices requiring unswitched 24-hour power should be connected to one of the auxiliary terminals, +VAUX. All negative terminals on the terminal strip are at the same reference and may be used whenever a common (circuit ground) negative is required. Use caution when wiring the control to distribute the load devices among the supply and the negative terminals evenly. NOTE: Circuit ground refers to any negative terminal connection on this control. This does not refer to the earth ground terminal or to the common terminals of Relay Output 3. These terminals are not at the same voltage potential and should not be wired so that they are electrically connected to a negative.

And, not directly M1 related but,
3) When using a reversing relay, +IN and -IN on a four-wire smoke detector are at +SAUX and -SAUX voltages (respectively) when not sounding, but are at -SAUX and +SAUX (respectively) when in alarm.

 

[Del91574]

First, even though not said in your post, make sure you know and understand which is circuit ground, panel ground and earth ground and COM of any panel outputs or output expanders. Confusion of which is which will cause huge headaches and potential panel or device damage or unpredictable results.


1. Yes, all driven off the same power supply on the board.

2. The panel carries a common negative through the Zcom's and VAUX-, but make sure you understand the differences between ground and 0VDC in this case. Those terminals are always at 0VDC irregardless of system status.

3. I'm assuming you're talking about the smoke detector itself, you'd need to verify the terminal designations for your devices, but yes and no. I think what you're asking is this:

Normal condition, the circuit is forward biased, in alarm condition the power is reverse biased. How that is accomplished varies based on what is involved, but those are the basics, and it really makes no difference if the power is from the panel or not because aux power supplies can be involved.

 

[Spanky]

All the negative terminals are common with the exception of output 2 which is switched to negative through a transistor for the siren or dc voltage operation selection.

 

[apu]

Thank you both -- confirmed my thoughts but I just wanted to be sure I wasn't misreading anything.