Tyco F3200 manual Open Collector Wiring, LED Mimic Displays, Interfacing to Other Equipment

F3200 Installation & Programming Manual		Document No: LT0122
Installation & Wiring
8.7	OPEN COLLECTOR WIRING

8.7.1LED MIMIC DISPLAYS

It is expected that the most common use the open collector outputs will be to switch LEDs on "mimic" displays. These outputs are approved for field connection, so may be used to "drive" remote mimics. Typical connection is shown in Fig 8.7.1.

8.7.2INTERFACING TO OTHER EQUIPMENT

Where the open collector outputs are used to switch inputs to other systems, such as an Evacuation System or Plant Computer, there are two main options as follows:

1.Direct Coupling

The open collector output switches the equipment input to less than 1V (typically 0.6V at 1mA). E.g. it may be used to switch a 5V CMOS input, or monitored 5V, 12V or 20V input. Refer to Fig 8.7.2.

Note that for this to work, the 0V supply of the equipment must be connected to the 0V supply of the FIP. This may not be desired, especially if the equipment has a power supply connection to earth.

Note also that the open collector output has protection diodes to the FIP positive and negative supplies and should not connected to inputs that could be "pulled" to a voltage above or below these supplies, even with mains failed and battery voltage low.

2.Isolated Coupling

The open collector output can be used to switch a relay, or an optocoupler as shown in Fig 8.7.3. When the open collector is "on", the optocoupler transistor is also "on".

	┌───┐
+VBF	│	├───────────────────────────────────────┬──────┬───────────────
	└───┘		┌┴┐		┌┴┐
			│ │		│ │ RESISTOR
			└┬┘		└┬┘ E.G. 4K7
				│	│
	┌───┐			∇		∇ LED
				│		│
OCn	│	├───────────────────────────────────────┘			│
	└───┘				│
	┌───┐				│
OCm	│	├──────────────────────────────────────────────┘

└───┘

FIG 8.7.1

EXAMPLE OF LED MIMIC WIRING

Page 8-22 5 July 2001 Issue 2.7