Input/Output; Technical Specifications; Figure 9: Troubleshooting Leds - Chamberlain LiftMaster Q Installation Manual

Input/Output

The Q Access Keypad is equipped with two output relays and four
factory dry contact inputs. Each input and output can be set for multiple
functions. The two relay outputs can be used to control doors, gates,
alarms, and other devices. The four dry contact inputs can be used to
monitor doors or trigger the special functions assigned to them.

Technical Specifications

Power Supply:
Voltage:
Current Consumption:
Relay Outputs (resistive load):
Maximum Switching Voltage:
Maximum Switching Current:
Maximum Switching Capacity:
Minimum Permissible Load:
Contact Resistance:
Life Expectancy:
Mechanical:
Electrical:
Inputs:
Dry Contact Type ONLY.
Do NOT apply voltage to any of the inputs.
Dry Contact Specifications:
Contact Resistance:
Current Capacity:
Environmental:
Ambient Temperature:
Ambient Humidity:
Note: The humidity inside the housing for any Q Access Keypad cannot
exceed 100% and must be noncondensing.
12 – 24VDC or 12 – 18VAC
300mA Maximum
30VAC/DC
AC: 10A (NO) / 3A (NC)
DC: 5A (NO) / 3A (NC)
1250VA (NO)
375VA (NC)
10mA at 5VDC
100mΩ Maximum
10,000,000 operations
200,000 operations minimum
(at maximum rated load)
500mΩ Maximum
100mA at 5VDC Minimum
-40°C to +80°C (-40°F to 176°F)
0% to 100% (see note)
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4. If there are multiple problems or ongoing issues, the process in the
previous step can be performed for an entire site. Generally, multiple
problems are a sign of problems in the wiring, either from bad splices,
pinched or nicked wires, radio frequency interference, water in the
conduit, or incorrect wire type. To check an entire site, allow for
access and egress of customers and open the housings and unplug
the power and data terminal blocks on every AI device on the site.
When every device on the site is unplugged, add one device back
into the system at a time. Allow that device to function for an hour
and then add in the next device in line. Eventually, a device will be
added that causes the problem to manifest. Switch this device with
one that has been previously added to verify if the problem exists in
the location or in the device.
5. Verify that all devices are receiving enough power. Create a voltage
map of the site by sketching out the locations of every AI device on
the site. Use a multimeter to take DC power readings at each device.
Note these readings on the sketch. Any device that is receiving less than
12V is underpowered and can cause the entire system to lock up.

Figure 9: Troubleshooting LEDs

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