Troubleshooting Keypad/Display; Keypad/Display Power Up Initialization - McQuay MicroTech II Installation And Maintenance Manual

addresses switches on the RS-485 communication
modules according to Table 4 on page 8. Apply
power to the control system and check operation. If
the problem follows the suspect communication
module, the module is defective. If the problem
remains with the suspect auxiliary control board,
the auxiliary control board is likely defective.

Troubleshooting Keypad/Display

Keypad/Display Power Up Initialization

When the keypad/display is connected to the MCB and
power is applied, the firmware in the keypad/display runs a
diagnostic test of its static RAM (SRAM) and will also
check the micro controller ROM for proper checksum. After
these tests are completed, the keypad/display will respond to
a poll of its address by the MCB with an acknowledge
message to the MCB. This will cause the controller to start
downloading display information to the keypad/display. The
keypad will be locked out until the tests and the download is
complete. Note: The keypad/display address is defined by a
four-position dip switch block on the right side of the device.
For this application, all four of these switches should be in
the UP position, which defines address 32.
When the keypad/display is connected to the MCB and
power is applied, the display has the backlight and the red
Alarm LED turned on. The backlight remains on until it
times out (15 minutes after a key press or after power up).
During the next 5 seconds, the LCD counts down from 9 to 0
in all 80 character locations. After the countdown is
complete, the Alarm LED turns off and the display appears
as follows:
Version xxx
Address yy
Status zz zzzz
Startup aaaa bbbb ccc
Where:
xxx = The version of firmware in the keypad/display
yy = The keypad/display address 32
zzzz = OK normally or NO COMM if the MCB is not
communicating with the keypad/display
aaaa = OK normally or IRAM of internal RAM test failed
bbbb = OK normally or XRAM if external RAM test failed
ccc = OK normally or ROM if ROM checksum does not
match stored checksum
When the MCB finishes downloading to the keypad/display
it sends a "download complete" message to the
keypad/display. When this message is received by the
keypad/display, the LCD will show the "main"
self-contained application menu screen.
Note: A NO COMM indication on the Status line during the
initialization period does not necessarily indicate a
problem. A communication problem is indicated if
40
the LCD remains indefinitely showing the
initialization display screen as shown above with the
Status line indicating NO COMM. In other words, the
LCD will not proceed to show the "main" application
menu screen.
If aaaa= IRAM, bbbb= XRAM and/or ccc= ROM, the
keypad/display must be replaced.
Note: The keypad/display may be connected to the MCB
while power is on. The normal elapsed time for the
"main" self-contained menu screen to appear in the
LCD upon initializing is approximately 60 seconds.
McQuay IM 710-1