Table of Contents
Advertisement
6.1.1.5
Resettable Fuse
Each sensor channel is provided with a PTC-resettable fuse internal to the DVP-120 to protect against over current situations. To reset
a sensor channel, power should be removed from the channel. This can be accomplished by removing power from the sensor – causing
the loop current to go to zero, or by completely removing power from the DVP-120.
6.1.2
Internal Controller Board Trouble
If the sensor status display and investigative efforts reveal no problems with the input channel current loops and channel configuration,
the most likely trouble condition is an internal problem detected by the DVP-120 controller. In this case, contact the Macurco Technical
Support at 1-844-325-3050 for advice and help.
6.2 Timed ventilation problem
When using the timed ventilation mode, the system clock should be checked regularly (at least twice a year). The battery-backed real
time clock in the DVP-120 does not adjust for daylight saving time so the spring and fall switch over points are good choices to check the
system clock.
High voltage terminals (120/240 VAC) are located within the DVP-120, presenting a hazard to service technicians. Only qualified
technicians should open the DVP-120 case and service the internal circuits. Ensure power is removed from the DVP-120 prior to servicing
the unit.
6.3 No Power
The DVP-120 starts up as soon as power is applied to the microcontroller, and the DVP-120 is designed to have power continuously
applied to the unit. An external indication of successful power application to the unit is the immediate operation of the Status Lamps
grouped around the LCD. If the operator does not see an immediate response from the status lamps, power should be checked at AC~.
If the correct voltage is noted at AC~, then the internal fuse of the DVP-120 should be investigated. The DVP-120 is protected from over-
current and transient situations by the fuse at F3. After removing power from the DVP-120, F3 can be checked by removing the safety
cover. If necessary, replace F3 with a 5x20 mm SLO-BLO fuse with a rating of 1 Amp 250V, e.g. Littelfuse P/N 218001. Be sure to
Replace the Safety Cover on F3 before re-applying power to the DVP-120.
DVP-120 may not function effectively below 32°F (0°C). Using the instrument below this temperature may adversely affect product
performance and result in serious injury or death.
6.4 LCD Display unreadable
It is possible that the LCD is unreadable due to temperature or aging of the control panel. If this is the case the following steps should
rectify the problem:
Hold the MENU key for three (3) seconds. After three seconds, the power led will turn red. After two additional seconds, the
•
LCD backlight will also be turned off.
Press the UP and DOWN cursor keys to change the LCD contrast. Each press of the UP or DOWN cursor key will change the
•
contrast by a step in that direction. Adjust the contrast for best viewing.
Press any other key to exit the contrast-setting mode.
•
6.5 The Keypad does not respond (LCD shows KEYS LOCKED)
The keypad can be unlocked by holding the zero (0) key for 3 seconds. At this time the backlight will turn on and the display will return
to normal mode. The keypad can again be locked by holding the zero key for 3 seconds until the display shows KEYS LOCKED.
WARNING
WARNING
46
Advertisement
Table of Contents
