Parker Hannifin
home | products | how to buy | support & downloads | literature | search

Click Here to go to new EM&D Knowledge Base (FAQ) site

PDS Replacement

The OEM750 is a very good possibility for replacing the PDS. They have the same basic capabilities, but there are a few hardware differences:

(The ZETA4, E-AC and ViX-IM are also options for replacing the PDS.)

POWER SUPPLY: The PDS took 110 and 240 Volts AC input. The OEM750 requires an external 24 - 75 VDC power supply. The OEM300 and OEM1000 both supply 75 VDC and can both take 120 and 240 VAC.

The ViX-IM requires a separate power supply that provides both 24 VDC for logic and 80 VDC or less for drive power.

The ZETA4 and E-AC are other alternatives that take 120VAC. The ZETA4-240 takes 240VAC.

BUS VOLTAGE: This directly affects the speed capability of the motor. The PDS's bus voltage was 70 VDC. The OEM750's bus voltage depends on the DC voltage being put into it; whatever DC voltage is put in is the bus voltage for the OEM750. Using an OEM300 which puts 75 VDC into the OEM750 will provide just slightly more performance than the PDS could. Likewise, using a different power supply that only puts 24 VDC into the OEM750 will make the OEM750 provide much LESS performance than the PDS could.

The bus voltage for the ViX-IM is 80VDC or less based on the external power supply.

The bus voltage for the ZETA4 and E-AC are both 170VDC. Some motors cannot be used with a bus voltage this high. Most of the motors used with the PDS can handle it. For example, the PDS-57-51 motor can be used with the ZETA4.
MOTOR RESOLUTION SETTING: The PDS had a default and maximum drive resolution of 4,000 steps/revolution. The OEM750 doesn't have that 4,000 setting. It does have 2,000 and 5,000. This will effect how many pulses are needed on the Step input to turn the motor one revolution.

The ViX-IM can have its drive resolution set to 4,000.

The ZETA4 and E-AC also do not have a 4,000 count resolution setting.

INTERNAL OSCILLATOR: The PDS had an internal oscillator that would allow a jog functionality with a potentiometer and an input without the need for an exteranl command signal. To replace this functionality, a drive with an indexer would be needed so that the jog functionality could be programmed. The OEM750X-M2 and ViX are both possible products for this type of functionality.

The E-AC with some custom functionality is also a possibility. Please see the FAQ for the E-AC titled "Can I get some level of control on the E-AC?"

Note: The PDSxx and PDSxx-2's are the same. Digiplan dropped the -2 on later models. So, a PDS13-2 and PDS13 are the same. The PDS15-2 and the PDS15 are the same. The /US designation does not signify a hardware change; only that it was originally sold from Parker Compumotor in the US.