Notes when commissioning a VSD mA module

Notes when commissioning a VSD mA module

1) Enable the use of an internal pressure sensor in Menu P03
  1. IP = 1 if internal pressure sensing is available
  2. IP = 0 if not internal pressure sensor is used
2) Select jumper setting on the XPM-Ao2 output card found inside of the VSD mA module


3) Menu P03, set up Ad (Network Address) of the compressor.
4) Calibrate the input and output pressure in menu P04 and P05. See page 23 of the VSD mA manual for more information.
5) Settings in menu P01 of the VSD mA module must match settings of the compressor controller.


6) Do a test to make sure the VSD mA module works properly. When the VSD mA module is stopped, pressure on the 1st and 2nd lines of the VSD mA display must be the same as the pressures on the compressor.
  1. Top line pressure on the VSD mA module is the real pressure reading from the pressure transducer.
  2. Second line pressure on the VSD mA module is the tricked pressure sent from the VSD mA module to the compressor controller.
  3. Pressure shown on the compressor is what it gets back from the VSD mA module.
Test:
When the VSD module is stopped, it’s not sending out a tricked pressure, so the 1st and 2nd lines will be the same (i.e. 96 psi). Pressure on the compressor controller must be the same as 1st line and 2nd line as well (i.e. 96 psi).
The 2nd picture of the asset controller shows a higher pressure of 101.5 psi. This means output pressure (P05) is not calibrated properly. 


Note: See below if using a Power$ync module (VSD module with special software)
With the Powe$ync interface module it is critical that the pressure on the 2nd line of the Power$ync module matches the pressure on the compressor controller. There can be 1 PSI difference but the compressor controller needs to see 1PSI higher than the 2nd line of the Power$ync module! Typically we make sure there is a difference of 10 PSI between Ph and Pl of the Power$ync module and Power$ync compressor controller.

Example:
Settings on the Powersync controller is 85 – 95 psi.
• At 85 psi, compressor loads. Powersync module will send a tricked pressure of 82 psi (3psi lower than 85psi) to make sure it loads.
• At 87 psi, 1st lift valve opens.
• At 89 psi, 2nd lift valve opens.
• At 91 psi, 3rd lift valve opens.
• At 93 psi, 4th lift valve opens.
• At 95 psi, compressor unloads. Powersync module will send a tricked pressure of 98 psi (3psi higher than 85psi) to make sure it unloads.

In order to open the 4th lift valve, Powersync module will send out 94 psi. However, if the compressor controller is 1psi less than 2nd line of the Powersync module, the compressor controller will see 95 psi tricked pressure and unload the compressor. Hence, the compressor controller must be 1psi HIGHER than the 2nd line of the Powersync module.

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