Flex MidContinent MD23-190 User manual

User Guide
For
MD23-190
Multifunction Clock
with GPS Synchronization
powered by
Rev
Date
Detail
Approved
1
12/09/2021
Initial release.
BAW
2
01/04/2022
Editorial updates.
BAW
This manual provides information intended for use by persons who, in accordance with current
regulatory requirements, are qualified to install this equipment. It is a supplement to the MD23
Installation Manual and Operating Instructions, p/n 9019161.
If further information is required, please contact Mid-Continent Instruments and Avionics.
Mid-Continent Instruments and Avionics Mid-Continent Instrument Co., Inc.
dba Mid-Continent Instruments and Avionics
User Guide UG190 9400 E. 34th Street N.
Revision 2 Wichita, KS 67226 USA
ph [phone]
www mcico.com

MD23-190
User Guide
Mid-Continent Instruments and Avionics 2 User Guide UG190, Revision 2
January , 2021
1.1 INTRODUCTION
The model MD23-190 multifunction clock is a standard 2-inch (2-¼”) panel-mounted instrument
that displays time, with or without an ARINC input for GPS synchronization, and offers several
timers and related time functions. Based on Mid-Continent Instruments and Avionics patented
FLEXTM Custom Function Display, this FAA and EASA TSO-approved instrument brings a highly
capable and modern addition to the cockpit to display required information and provide useful
supplementary functions.
This User Guide is a supplement to the Installation Manual and Operating Instructions (IM),
MCIA part number 9019161. The IM contains all information associated with the standard
product, including installation procedures, product specifications, operating instructions,
certification data, and maintenance requirements. This User Guide provides additional
information associated with the specific features of the multifunction digital counter drum
altimeter. It addresses product identification, electrical pinout, initial configuration setup, and in-
flight user operation.
1.2 PRODUCT IDENTIFICATION
Each MD23 is comprised of certified hardware and certified software. Within the context of the
certified software is a set of data items that can configure and customize the behavior of the unit.
This set of data is referred to as a Custom Instrument Definition, or a CID file. The CID file for
this instrument is pre-loaded and may be available for future updates via a standard USB flash
drive through the programming port on the rear of the unit.
A unique CID number has been assigned specifically to this application. The CID is identified by
its two-digit number and an alphabetic character representing the CID version, starting with “A”.
The identification of the hardware, software, and CID configurations are listed below. Both the
software version and the CID can be viewed on the Introduction Screen during the first few
seconds of applying power to the unit. This information can also be accessed on the Info page of
the Options Menu during Flight Mode.
1.3 PRODUCT FUNCTION
The CID identified within this User Guide is designed as a multi-function clock. It displays UTC
time and Local time and contains multiple timers such as count up, count down, and Elapsed
Flight time. It can receive ARINC 429 inputs to provide time synchronization with a GPS source
and Estimated Time to Waypoint. The highly accurate internal clock maintains time to ±2 minutes
per year when not sync’d, including a 10-year internal battery to keep time when the unit is
powered off. Additional Hobbs and Run timers track usage over the life of the product with the
Flight and Hobbs timers capable of being triggered via an external signal. The clock can also
output currently displayed time via ARINC to external equipment.
Unit Versions
Hardware Part Number
Software Version
CID
6420023-1
1.0.2, or later
90A, or later

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2.1 CONNECTOR PINOUT
For standard pre-installation and installation instructions, including location, cable harness
assembly, pneumatic inputs (if applicable), mounting, and others, please refer to the IM.
Pinout identification specific to this CID is listed in the table below. A brief description is provided.
Further definition of the inputs and outputs should be documented in the technical requirements
and/or statement of work and are not provided within this User Guide.
Connector Pinout
Pin
Description
Function
1
Ground
Power return; connect to a/c ground
2
ARINC Out (A)
ARINC label 150
3
ARINC Out (B)
(paired with pin 2)
4
Dimmer Input
5, 14, or 28VDC input (if used)
5
ARINC In 1(A)
ARINC labels 150, 252
6
ARINC In 2(A)
Reserved
7
Reserved
8
Reserved
9
Reserved
10
Reserved
11
Reserved
12
Reserved
13
Reserved
14
ARINC In 1(B)
(paired with pin 5)
15
Reserved
16
ARINC In 2(B)
Reserved
17
Reserved
18
Reserved
19
Power Input
+10-32VDC
20
Reserved
21
Reserved
22
Discrete Input
Flight Timer Start/Stop Signal
23
Discrete Input
Hobbs Timer Start/Stop Signal
24
Reserved
25
Reserved
26
Reserved
Table 1 Unit Connector Pin Identification

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3.1 CONFIGURATION AND SETUP
Enter Configuration Mode by pressing and holding the Control Knob while applying power to the
unit. For configuration and setup of standard unit functions, including dimming control options
and dimming curve definition, please refer to the IM.
Configuration settings specific to this CID are found within the User Configuration menu option.
The User Configuration items include two functions:
•Flight Timer (FT) Options:
oselect MANUAL to start and stop the Flight Timer manually
oselect EXTERNAL to start the timer on an open signal. Timer stops when grounded
•Hobbs Timer Pre-Set: (to coincide with the existing aircraft/engine time basis)
oenter password 1238. This is constant for all units with this CID. Anyone with this
password can reset or change the Hobbs timer
oenter the desired pre-set value for the Hobbs timer
Flight Timer Configuration Options Hobbs Timer Set Page
4.1 OPERATION
For operation of standard unit functions, including the Options Menu, manual brightness control,
Info page, and others, please refer to the IM.
4.1.1 DISPLAY PRESENTATION
In Flight Mode, the display is presented as shown in the example figures below.
Power on screen Normal Operation
(example)

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The main display is divided into three segmented areas –the upper, middle, and lower
panes. Operation of each function and examples images are shown below.
Turning the Control Knob right or left rotates between functions or indexes digits and
highlights that element GREEN when selected. Pressing the Control Knob selects or toggles
a highlighted function or sets a selected digital value and sequences to the next.
UPPER PANE
The Upper Pane always shows the time, time zone (UTC or LOCAL) and date. It also shows
the status of the GPS time synchronization signal. See TIME under the Functions section for
more details.
MIDDLE PANE
The Middle Pane provides control and an expanded view of one of the functions selected
from the Lower Pane. When the unit is initially powered on, the Middle Pane is blank.
LOWER PANE
The Lower Pane shows the current active value of all four timer functions and allows any of
them to be selected for an expanded view and control in the Middle Pane. The Middle Pane
can be manually turned off by re-selecting the currently active function in the Lower Pane.
4.1.2 CLOCK FUNCTIONS
TIME
When highlighting and selecting the current time zone in the Upper Pane (either UTC or
LOCAL), three options become available to scroll and select between UTC, LOCAL, or
LOCAL SET.
In LOCAL SET mode, the hour and minutes can be changed to the desired values.
A satellite icon is shown in either gray (off) or white (on) depending on whether the unit is
currently receiving and synchronized with the GPS time from the incoming ARINC 429 signal.
When no incoming signal is received or the unit is off, the unit maintains accurate time based
on its internal clock and will re-synchronize when the signal is available.
Normal View Time Zone Options
(UTC mode shown) (Local Set mode shown)

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Flight Timer (FLT)
When the Flight Timer is selected from the Lower Pane, the Lower Pane will show MM:SS
and the Middle Pane will show the HH:MM:SS for the first minute. After the first minute, the
Lower and Middle Pane will show HH:MM, with the Middle Pane also showing :SS, if that
feature is set to ON in the Seconds Option menu (see 4.1.3).
When the Flight Timer is configured for Manual mode, the user can START, STOP, and
RESET the timer manually by scrolling to and selecting the desired action. If RESET is
selected without first selecting STOP, the timer will reset to zero and continue counting.
When the Flight Timer is configured for External mode, no control options are available. The
start and stop functions are determined by the input signal and reset upon power cycle.
Flight Timer Flight Timer
(Manual Mode) (External Mode)
Estimated Time to Waypoint (WP)
When the WP Timer is selected from the Lower Pane, the Lower Pane and Middle Pane will
show HH:MM. There are no control options in WP mode. The Estimate Time to Waypoint is
supplied via external input source (ARINC Label 252, also known as “Time To Go”).
WP Timer
(if available)

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Count-up Timer (T)
When the Count-up Timer (also referred to as elapsed timer, stopwatch, or chronograph) is
selected from the Lower Pane, the Lower Pane and Middle Pane will show HH:MM:SS. The
user can START, STOP, and RESET the timer manually by scrolling to and selecting the
desired action. If RESET is selected without first selecting STOP, the timer will reset to zero
and continue counting.
Count-up Timer
(running)
Count-down Timer (T)
When the Count-down Timer is selected from the Lower Pane, the Lower Pane and Middle
Pane will show HH:MM:SS. The user can SET, START, STOP, and RESET the timer
manually by scrolling to and selecting the desired action. When SET is selected, turning the
Control Knob changes the digits and pushing it sequences from hours to minutes to seconds.
Once activated, when the timer reaches zero, it will begin counting up, show a plus (+) in
front of the timer, and turn the digits yellow. If RESET is selected without first selecting
STOP, the timer will reset to its original setting and continue counting.
Count-down Timer Count-down Timer
(during Setting) (count-up after timer reaches zero)

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Summary of Display and Functions:
•Upper Pane
oTime/Date: Select and display UTC or Local Time; Displays date
▪Set: Allows user to set Local Time
▪Sync Icon: Displays Sync status; white = on, gray = off
•Middle Pane
oCurrent Timer: Enlarged view and control of the currently selected timer
Timers have specific functions that may include stop/start/reset/set
•Lower Pane
oTimer Options: Displays available timers with current activity
▪FLT (Flight): Manually start/stop/reset or controlled via input signal
(weight-on-wheels, engine start relay, etc)
▪WP: Available only if provided via external ARINC input
▪T(Count-up): Stopwatch function with manual start/stop/reset
▪T(Count-down): Count-down timer from user set value with manual
start/stop/reset; counts up after reaching zero
4.1.3 USER OPTIONS
Pressing and holding the Control Knob for three (3) seconds will activate the Options Menu.
The manual brightness adjustment and info page are described in the IM. The Options Menu
or User Options items will close and return to the active display after five (5) seconds if no
activity is recorded.
When highlighted and selected, the User Options item will open a new page and display the
available options available to the user during Flight Mode. The User Options and their
descriptions are listed below.
Highlight and select Exit to return to the Options Menu or simply wait five (5) seconds and the
unit will return to the active Flight Mode display.
Options Menu User Options Menu

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Time Format
The Time Format menu can set the Local Time to 12-HR or 24-HR mode. UTC time will
always be shown in 24-HR model. This page will also identify which mode is currently active.
Time Formal Menu
Time Set
The Time Set menu allows the user to set UTC time or Local Time. GPS time is shown if
currently available.
The UTC time can be set to a different time than the GPS time, even when GPS time is
available. In this case, the time basis will continue to be synchronized, but the manual UTC
time will be stored and remembered as an offset to the GPS time. The SYNC UTC function
can be used to reset a manually modified UTC time back to GPS time (if GPS time is
currently available).
Seconds can only be set/reset to zero. UTC seconds cannot be set if a current GPS time is
available; it will always be synchronized with GPS seconds. Local seconds cannot be set; it
will always be synchronized with UTC seconds.
Time Set Menu Time Set Menu
(GPS time not available) (GPS time available)

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Date Set
The Date Set menu allows the user to set the date. The internal calendar will keep an
accurate date through the year 2099.
Date Set Menu
Seconds Option
The Seconds Option menu allows the user to choose whether the seconds (HH:MM:SS) are
shown (ON) or not shown (OFF) on the main display for both the time (UTC and LOCAL) and
the Flight Timer. This feature is to reduce clutter or distraction per user preference.
Seconds Option Menu
Timers
The Timers menu displays two informational timers. The Run Timer shows hours that the unit
has been powered on since inception. The Hobbs Timer shows hours of aircraft operation
based on an external start and stop signal provided by the aircraft.
Timers Menu

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Summary of User Option Menu items and their function:
•Time Format Set 12 or 24-hour time display; applies to Local Time only
•Time Set Set UTC and Local Time
UTC can be set as an offset to GPS time or independently when Sync
is not on/available
SYNC UTC resets UTC to GPS time (if available)
•Date Set Set date
•Display Seconds Enable display of seconds (on/off) for Clock and Flight Timer
•GPS Sync Sets GPS Sync to on or off; if available
•Timers Displays Run timer (total power-on time of the unit)
Displays Hobbs timer (if enabled via external signal)
5.1 CONFORMANCE
For standard conformance items such as qualification levels and software updates, please refer
to the IM.
5.1.1 INSTRUCTIONS FOR CONTINUED AIRWORTHINESS
No periodic scheduled maintenance or calibration is necessary for continued airworthiness of
the MD23 Custom Function Display, unless specified in the aircraft maintenance procedures.
The unit display can be cleaned using a lint-free cloth moistened with water. No chemicals
should be used to clean the display.
If the unit fails to perform to specifications, the unit must be removed and serviced by Mid-
Continent Instruments and Avionics or their authorized designee. Other than software or CID
version updates, there are no repairable parts or processes available to be performed in the
field.