Vmax-VFD Medical Duplex-Triplex-Quadplex Operational Instructions

For use with VmaxVFD industrial vacuum systems equipped with VFD’s and Sequencing Panel

Each Vmax system is tested and checked at the factory prior to shipment to ensure trouble free-operation. In the unlikely event you encounter a problem, we recommend that you consult with your local distributor for parts/service. Remember, when calling for service, parts or system information, always have the pump or system model number and serial number ready. 

Click here to find your local authorized distributor

Industrial Duplex - Triplex - Quadplex Vacuum System Description

The DEKKER Duplex - Triplex - Quadplex vacuum system can consist of two, three or four Vmax liquid ring vacuum pump systems. Each vacuum pump system has a separate VFD control panel. An additional sequencing panel includes a PLC and a PID process controller for sequencing, alternation and PI motor speed control.

An intelligent PLC program monitors which pumps are available and which pumps adjusts the sequencing to accommodate changing status. If pumps are powered down for routine maintenance, or turned off at their HOA switches, the program will skip the unavailable pump(s). For example, a triplex system with any single pump powered off will function as a duplex. A quadplex system with any single pump powered off will function as a triplex.

Alternation routines in the PLC program check elapsed run-time hours for each pump once every 24 hours at 1:00 a.m. Lead, Lag1, Lag2 and Lag3 status are re¬assigned based on usage. The available pump with the next fewest hours will be assigned as Lag1, etc. The PLC program also checks hours when first powered up.

The PLC sequencing program recognizes an available pump as one whose panel is:

  • Powered
  • Not in alarm
  • HOA switch is in the Auto position

The Hand position starts the pump at full VFD speed (60 Hz). While in the Hand or Off position, a pump is considered unavailable to the PLC controller program and is taken out of the automatic sequencing.

 

Typical Operation

In normal operation, all pumps are in the HOA switch Auto position. After first powering up the sequencing panel, the PLC will initialize within 15 seconds. The program will assign Lead, Lag1, Lag2 and Lag3 status based on the run-time hours for each pump.

The PLC program will continuously monitor actual vacuum level, which also appears on the red LED display of the process controller. The Lead pump will turn on when vacuum level falls to the Lead On threshold value. Pump speed is controlled by the VFD in each pump control panel and will slow the pump as vacuum setpoint is achieved. Minimum speed for the VFD is set at 37.5 Hz. If vacuum demand increases, and the vacuum level falls to the Lag1 On threshold, the program will start the Lag1 pump.

Pumps are sequenced off in a similar manner, but in reverse order. As vacuum level increases, pumps will turn off at their respective Off thresholds. When an Off threshold is reached, that pump will continue to run for a preset minimum time of 10 minutes. During this time, the PLC display will indicate MIN for that pump. At the end of the minimum run time, that pump will shut off and its display will change to RDY to indicate the pump is in a Ready mode. If the vacuum level falls again below the On threshold, the PLC display for that pump will change back to Ld, LG1, LG2 or LG3. The pump will automatically turn back on.

 

Lag Alarm

The lag alarm is intended to indicate when the reserve pump is in use. The red Lag Alarm lamp will light and the Lag Alarm dry contacts will change state. This will occur when the last available pump turns on.

An audible horn will sound whenever the lag alarm activates. This horn can be silenced by pressing the Horn Silence button on the sequencing panel. The Lag Alarm lamp will remain lighted and the Lag Alarm dry contacts will stay in alarm until reset with the Alarm Condition Reset button. Note that the lag alarm cannot be reset until the reserve pump Off threshold is reached. This will be indicated by the display for that pump changing to MIN or after the 10-minute minimum run time to RDY.

 

Screen Definitions

PLC Main Screen Definitions 

NR = Not Ready / The VFD HOA switch is either in Hand position or the Off position, or the VFD panel is powered off, or
the VFD panel is in alarm status.
RDY = Ready / The VFD HOA switch is in the Auto position but the pump is not running.
HND = Hand / The VFD HOA switch is in the Hand position.
LD = Lead / The VFD HOA switch is in the Auto position and the pump is running as the Lead pump.
LG1 = Lag 1 / The VFD HOA switch is in the Auto position and running as the first Lag pump in the sequence.
LG2 = Lag 2 / The VFD HOA switch is in the Auto position and running as the second Lag pump in the sequence.
LG3 = Lag 3 / The VFD HOA switch is in the Auto position and running as the third Lag pump in the sequence.
MIN = Minimum Run Time / The VFD has reached its threshold vacuum and is running a preset minimum run time before
shutting off.

Top Right Corner of Main Screen

Q = Quad Mode / The system is running as a quadplex system with four pumps.
T = Triplex Mode / The system is running as a triplex system with three pumps.
D = Duplex Mode / The system is running as a duplex system with two pumps.
S = Simplex Mode / The system is running as a simplex system with one pump.
* = No VFDs are available in Auto mode

 

Setting Date and Time

Before running the system, the date and time should be checked and set if needed. Press the Right arrow key on the keypad. While still holding the Right arrow key, press the Left arrow key. Enter the current date by using the keypad. As you change the date, the cursor will move to the next position. After entering the date, press Enter to move to the next line and enter the time. When finished, press Enter again to save the settings. Press Enter once more to go back to the main screen.

Date Format = dd/mm/yy
Time Format = HH:MM:SS Military (example: 10:00 p.m. = 20:00:00)

 

Changing Lead / Lag Setpoints

The On and Off thresholds for Lead, Lag1, Lag2 and Lag3 are factory set on the Unitronics PLC at the most efficient values and should not be changed.

Lead On = 302 Torr = 18” HgV
Lead Off = 226 Torr = 21” HgV

Lag1 On = 315 Torr = 17.5” HgV
Lag1 Off = 239 Torr = 20.5” HgV

Lag2 On = 328 Torr = 17” HgV
Lag2 Off = 252 Torr = 20” HgV

Lag3 On = 340 Torr = 16.5” HgV
Lag3 Off = 264 Torr = 19.5” HgV

 

Troubleshooting_PLC_Image_121

 

Watlow PLC vacuum setpoint = 283 Torr = 18.75” HgV.
Recommended range for the pump thresholds is 290 to 277 Torr (18.5” HgV to 19” HgV).
Vacuum setpoint appears as a green LED readout on the process controller.
Up/Down arrow keys can be used to adjust this value.
If On/Off threshold changes are made in the PLC, the vacuum setpoint in the Watlow process controller may also require
change and vice versa.

 

Lead

Troubleshooting_PLC_Image_122

 

To change the On and Off values for the Lead pump, press the Right arrow key; while still holding the Right arrow key, press
the #1 key.
Enter the value (in Torr) for the Lead pump to turn on, then press the Enter key.
Enter the value (in Torr) for the Lead pump to turn off, then press the Enter key.
Press Enter once more to return to the main screen.

Lag 1
To change the On and Off values for the Lag 1 pump, press the Right arrow key; while still holding the Right arrow key, press
the #2 key.
Enter the value (in Torr) for the Lag 1 pump to turn on, then press the Enter key.
Enter the value (in Torr) for the Lag 1 pump to turn off, then press the Enter key.
Press Enter once more to return to the main screen.

Lag 2
To change the On and Off values for the Lag 2 pump, press the Right arrow key; while still holding the Right arrow key, press
the #3 key.
Enter the value (in Torr) for the Lag 2 pump to turn on, then press the Enter key.
Enter the value (in Torr) for the Lag 2 pump to turn off, then press the Enter key.
Press Enter once more to return to the main screen.

Lag 3
To change the On and Off values for the Lag 3 pump, press the Right arrow key; while still holding the Right arrow key, press
the #4 key.
Enter the value (in Torr) for the Lag 3 pump to turn on, then press the Enter key.
Enter the value (in Torr) for the Lag 3 pump to turn off, then press the Enter key.
Press Enter once more to return to the main screen.

 

Manual (Forced) Alternation

To manually alternate the Lead and Lag pump sequence, regardless of actual hours used, press the +/ key. Each button press will advance the pump order sequence one step.

To manually alternate the Lead and Lag sequence, based on actual hours used, press the Right arrow key and the +/ key

 

Download the PDF