Omega Vehicle Security OM5-C manual P1 Connector, Address Selection, 15, Expanded

ELECTRICAL

P1 CONNECTOR

The 26 pin P1 connector provides the signal interface between the OM5-BP- 16-MUX-C backpanel and the host measurement system. Two separate analog bus connections are provided; one for analog input signals and one for analog output signals. Two sets of six address lines and an enable pin allow input and output modules to be independently multiplexed onto their respective analog signal bus. R0 thru R5 and RDENAB are used for input modules, and W0 thru W5 and WRENAB are used for output modules.

ADDRESS SELECTION

The OM5-BP-16-MUX-C backpanel has address decoding circuitry to allow multiplexing any combination of up to 16 input or output modules. Capability is also provided in the address decode circuitry to expand the system to 64 channels (four OM5-BP-16-MUX-C backpanels) of multiplexed input or output. Jumpers on HD10 header, E1 and E2 group, select which set of 16 addresses are assigned to a particular backpanel. The E1 group assigns a set of 16 addresses for input modules, and the E2 group assigns a set of 16 addresses for output modules. The table below shows the correlation of jumper position to address range.

E1 Jumper Pos	E2 Jumper Pos	Address Range/Mode
4	4	0-15, STAND ALONE
3	3	48-63, EXPANDED
2	2	32-47, EXPANDED
1	1	16-31, EXPANDED
0	0	0-15, EXPANDED

To connect multiple OM5-BP-16-MUX-C backpanels in this expanded configuration, use interconnect cable OM5-CAB-01-C.

POWER

The OM5-BP-16-MUX-C backpanel requires external +5VDC ±5% power. The chassis mounted OMX-976 power supplies have adequate capacity to power any combination of modules.

FUSING

The OM5-BP-16-MUX-C backpanel power is fuse protected through F1. This is a Littlefuse type 252004, 4 amp fuse. Zener diode DZ1 provides extra protection by clamping the input power voltage to +5.6V. If the input supply voltage connection is reversed, this zener diode will be forward biased and fuse F1 will be blown.

GROUNDING

Figure 7 below details the optional ground jumper configuration available on the OM5-BP-16-MUX-C backpanel. Jumpers J1, J2, and J4 are factory installed.

Jumper J1 connects the SIG COM shield wires (pins 2, 5, and 6) to the backpanel signal ground. This provides a ground connection between the host system and backpanel. Jumper J1 is required if output modules are used, or if there is no high impedance sense input (input low of a differential or pseudo-differential system) on the host measurement system.

Jumper J2 connects the SNS LO line (pin 4) to the backpanel signal ground. If the host system has the capability, this allows measuring the OM5-BP-16- MUX-C ground potential.

For proper operation of the output switch or track-and-hold circuit when using the OM5-BP-16 backpanels, a current path must exist between the host control logic power common and module I/O Common (module pin 19). This path can be established on the OM5-BP-16-MUX-C via jumper J4. If this connection exists elsewhere in the system, jumper J4 should be removed since possible ground loops could exist. Other connections of power ground and signal ground usually occur at the A/D or D/A converter of the host measurement system.

If the connection of power common and SIG COM shield wires exist in the host measurement system, a resistive connection between SIG COM and the backpanel signal ground can be made via R1. R1 can be as large as 10K ohms; 100 ohms is a recommended value. Jumper J3 can be used to connect the SNS LO line to R1 when this ground configuration is used.

For full protection against large electrical disturbances on the field-side of the OM5 modules, a #10-32 ground stud is provided on the backpanel. An electrical connection between this ground stud and system ground should be provided with a large gauge wire of the shortest possible length. When this connection is made, a possible ground loop could result through the SIG COM shield wires and backpanel signal ground. If the application involves only input modules and a differential input is used by the host measurement system, J1 should be removed. Remember that J1 is required if output modules are used or if the host system does not have differential inputs.

P1			OM5 Module
2	SIG COM
5	SIG COM
6	SIG COM		I/O COM 19	16	PWR COM
4	SIG COM	J2	J4
		J3	Power Common
		J1
		R1	Signal Ground
			and
			Grounding Bolt
FIGURE 7. OM5-BP-16-MUX-C Grounding Diagram.

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