Technical Specifications  
890CS Common Bus Supply - Frames B & D; 890CD Common Bus Drive and 890SD Standalone Drive - Frames B, C & D  Page E-41 
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Auxiliary Power Supply Load Requirements 
This tables lists the auxiliary power supply requirements for the 890 units and ancillary equipment, 
assuming normal operating conditions with maximum SMPS and fan loads.  
Item  Load Requirements  Item  Load Requirements 
Tech Cards - Speed Feedback 
8902/EQ : HTTL Encoder  8W  8902/E1 : Sin/Cos Encoder  3.3W 
8902/RE : Resolver  3.2W     
Tech Cards - Communications 
8903/DN : DeviceNet   1.3W  8903/RS : RS485 (Modbus)  1.3W 
8903/FA : Firewire  0.7W  8903/PB : Profibus  2.3W 
8903/CN : ControlNet  1.3W  8903/CB : CANOpen  1.3W 
Keypads 
6511 Keypad  0.9W  6901 Keypad  1W 
Worked Examples 
To calculate the total requirement for an 890CS Frame D fitted with a 6511 keypad: 
  Power  = 24 + 10.2 (fan load) + 0.9  = 35.1W,   Input Current @ +24V = 35.1 / 24 = 1.463A 
To calculate the total requirement for an 890CD Frame D fitted with a 6511 keypad and Profibus Tech Card: 
  Power  = 20 + 0.9 + 2.3  = 23.2W,   Input Current @ +24V = 23.2 / 24 = 0.967A 
IMPORTANT 
The 890's internal +24V SMPS has a 3A current limit which is used during start-up. 
In a system containing ten 890 units for example, the initial loading will be 10 x 3A for approximately 50ms during 
start-up, i.e. 30A. Consequently, the customer auxiliary SMPS +24V power supply must be able to over-load for a 
brief time to accommodate the start-up condition.