Design Considerations for the Mx Controller

This section documents the procedures for mounting, configuring, wiring, and powering an Mx Controller. Controllers are usually located in a safe and secure area, such as an electrical room, telephone equipment room, closet, or the security operations office. An environmentally managed room is not required if the temperature ranges don’t exceed the Controller’s specifications.

In addition to monitoring, reporting, and controlling a variety of devices, each controller can power a specific number of ScramblePads, MATCH2 interfaces, and attached readers. Other devices, such as interior motion sensors and some readers, may require power from a separate power supply.

Electrical Ratings

An Mx controller has the following electrical ratings:

Mx Controller Design

Depending on its configuration, an Mx Controller provides for 2, 4, or 8 supervised doors: this includes 5Amp door relays with line module inputs. Each door is represented by a ScramblePad/MATCH terminal block, a Weigand terminal block, a relay terminal block, and an input terminal block (for connecting a line module). An Mx Controller can power ScramblePads and MATCH2 interfaces from the 5-pin MATCH terminal blocks, or it can power Weigand card readers from the 6-pin Weigand terminal blocks.

Starting with the Velocity 3.6 SP2.1 release and the CCM/CCMx firmware 7.5.70.12 release, on an Mx-2 or Mx-4 controller where Wiegand terminals are available from unused doors, some of those available terminals can easily be used for exit readers. For details, see “Connecting Exit Readers to Unused Wiegand Terminals on Mx-2 or Mx-4 Controllers”.

An Mx Controller includes an integrated SNIB2 for direct connection via RS-485 to a SCRAMBLE*NET network and an integrated Ethernet port for easy connection to a computer running Velocity. It also supports certain optional expansion boards, as discussed in “Expansion Boards for the Mx Controller”.

Locate the controller near a dedicated AC power source. A 15Amp dedicated, unswitched circuit is required. If the power in the building is correctly grounded, there is no special grounding required for the controller. The entry point for the primary AC power is through the bottom or back of the enclosure. Connect AC power under the protective cover onto the supplied terminal strip.

Separation of Circuits

As shown in the following figure, the Class 1 high-voltage AC input power for an Mx controller is routed through either one of the two knock-outs at the bottom of the enclosure, while the cables for the controller’s Class 2 circuits (such as HI/LO inputs, MATCH reader terminals, and Wiegand reader terminals) are routed through several knock-outs located across the top and sides of the enclosure:

Figure 2-3: Cable Inlets of the Mx Controller’s Enclosure

The Mx controller’s Class 2 limited-power circuits include the following connections (as shown in Figure 2-2, “Mx Controller Main Board Connectors and Components”, in section “Mx Controller Main Board”:

• 8 3-wire HI/LO analog input terminal blocks (for the line modules used to supervise doors, tamper circuits, and RQE devices).

• 8 5-wire MATCH terminal blocks (for connecting keypads or readers through the 28 VDC MATCH2 Reader Interface). These are digital circuits which support MATCH2 boards and DS47L series keypads.

• 8 6-wire Wiegand terminal blocks (for connecting the wiring from a 12VDC keypad or reader with a Wiegand interface). These are designed to support a variety of 125 kHz and 13.56 MHz readers and credentials.

• The 5-wire SNIB2 RS485 terminal block (and its associated DIP switches) enables you to securely communicate with downstream controllers on a private network (which is managed by the same Velocity server).

• The Expansion Board Connector is used to link any expansion boards mounted in the controller’s enclosure to the controller’s main board (using a flexible EBIC5 ribbon cable).

All reader circuits are protected by resettable thermal fuses, which automatically restore circuit integrity after the overcurrent has been removed. When routing the wires for the Class 2 limited-power circuits, make sure that you maintain a safe separation of at least 0.25 inches from the wires for the AC input power and the standby battery pack.

A complete list of the Mx controller’s Class 2 limited-power connectors is available in “Class 2 Limited-Power Connectors on an Mx Controller”.

Mx Controller Standby Battery Capacity

The Mx-2 controller comes factory-equipped with a 24V 1.3 Ah battery. The Mx-4 and Mx-8 controllers come factory-equipped with a 24V 7.2 Ah battery, to comply with the standby power requirements of UL 1076 Section 40. Each battery kit consists of two 12-volt batteries connected in series for a full 24-volt standby unit.

If still more backup power is required, the provided internal standby battery can be replaced by larger-capacity external 24VDC batteries (up to a limit of 14 amp-hours), or by a charger and batteries (such as those made by AlarmSafe). A 120/240VAC UPS can also be tied into the main power, providing the controller with both surge protection and emergency power.

When using either external batteries or a charger and batteries, remember:

• When using an external battery pack, remove the controller’s internal battery and connect the new power line into the unused standby battery input on the controller board. Remember: connecting two similar batteries in series doubles the voltage.

• When using a UPS, connect the UPS into the AC power line.

To determine how much backup battery power a particular controller requires, use this formula:

( I_Devices + I_Controller ) x hours = Battery Life Required

This is the sum of the load at 24VDC of all the attached devices plus the load at 24VDC of the controller itself, multiplied by the hours of battery operation required. Table 2-4 provides the extended standby battery requirements (current draw in amps) for the Mx Controllers and typical system components, based on quiescent (idle) conditions:

Table 2-4: Quiescent Current Draw for the Mx Controller and Various System Components

For example, suppose an Mx controller is connected via MATCH2 Interfaces to four doors, each of which is using dual technology: 4 ScramblePads – 2 regular for interior and 2 high intensity for exterior – together with 4 CR11L mag stripe readers.

The installed example system’s current draw is itemized:

A factory-installed 7.2 Ah battery pack (supplied with an Mx-4 or Mx-8 controller) could support this configuration for:

However, if you specify that the extended standby battery backup requirement must be at least 8 hours of operation without primary power:

1.49A x 8 hours = 11.92 Amp-hours

Obviously the included 7.2 Ah battery pack is not sufficient for this system. To operate this system without primary power for a full 8 hours, you will need to provide either an external battery or a front-end UPS, with at least a 12 Ah capacity.

Power Provided at the Mx Controller’s Terminal Blocks

An Mx Controller provides 12VDC power at the Wiegand terminal blocks, and 24VDC power at the MATCH terminal blocks.
The following table shows the power provided for Wiegand and MATCH@ keypads/readers by an MX Controller.

Table 2-5: Maximum Current Draws for an Mx Controller’s Terminals

ScramblePad/MATCH2 Power Requirements

To determine how many ScramblePads and MATCH2 interfaces an Mx controller can power, you must calculate the current draw of the ScramblePads and MATCH2 Interfaces and compare it to the maximum current draw available from the Mx controller (which is shown in the MATCH row of Table 2-5).

The controller powers ScramblePads and the MATCH2, then the MATCH2 powers one or two readers. The Mx controller has an integrated MATCH terminal and an integrated Wiegand terminal for each door, which can power the readers directly wired to those terminals.

Figure 2-4: Current Draw Orientation for MATCH2 Interface

As shown in Figure 2-4, voltage from the Controller to the MATCH2 and ScramblePads is 24VDC, while voltage from the MATCH2 to its connected readers is 5VDC. (Although ScramblePads may be connected through the MATCH2 to the controller, the ScramblePads are powered by the controller, not the MATCH2.)

To determine how many ScramblePads and MATCH2 interfaces the controller can power, use the following procedure:

1. Determine what devices you will be using. For example, an Mx-4, DS47L ScrambleProx, an MRIB MATCH2 Interface, and MATCH-compatible readers.

2. Determine the quantity of each device you’ll need. For example, 1 Mx-4, 1 DS47LSPX and 1 DS47L-SPX-HI ScrambleProx, 1 MRIB, and 2 CR31L readers.

3. Determine whether the MATCH2 Interface will be able to power the connected readers. Make sure the readers’ 5VDC draw does not exceed the MATCH2’s 250mA at 5VDC limit. If the MATCH2 powers readers, it draws more current from the controller than if the readers were separately powered.

4. To determine the current draw of each attached device on the controller at 24VDC, multiply the number of devices by the current draw for each device, then add the total for each device to calculate the Total Current Draw required from the controller, using the values shown in Table 2-6:

Table 2-6: ScramblePad/MATCH2 Current Draw

As shown in Table 2-6, it doesn’t matter to the controller whether a MATCH2 is powering one or two readers, because the MATCH2 is using a switching power supply. The MATCH2 can provide up to 250 mA @ 5VDC to each of two readers and present a load to the controller of only 200 mA @ 24VDC. If readers attached to
a MATCH2 are self-powered, the MATCH2 presents a load to the controller of only 70 mA.

For this example, given both entry and exit dual technology – 1 DS47L-SPX-HI ScrambleProx and 1 CR31L Wiegand Swipe Reader on the entry side, and a DS47LSPX ScrambleProx and 1 CR31L on the exit side – tied into a MATCH2 interface, the following calculations would result:

5. Determine whether an Mx controller can power the ScramblePads/MATCH2s connected to it, by comparing the Total Current Draw required against the maximum current draw available from the controller (which is shown in the MATCH row of Table 2-5).
6. Verify that current from any one ScramblePad/MATCH terminal block does not exceed 1.0 Amp.

The preceding total of 0.535A is well within an Mx Controller’s 1.0A per channel limit and 2.9A total capacity limit. If the total current draw required exceeds an Mx controller’s limits, use a remote power supply for one or more of the attached devices.