Measurement Computing WBK17 - Manual (Page 22)

WBK17, pg. 22 987996 WBK17, Counter/Encoder Module
Encoder Wiring Diagrams
You can use up to four encoders with each WBK17 module in your WaveBook system. Each A and B
signal can be made as a single-ended connection with respect to common ground, or as a differential
connection.
Encoder wiring diagrams and example setup tables are included in the following pages; refer to them as
needed.
For Single-ended Connections:
For single-ended applications, the connections made from the encoder to WBK17’s front panel are as
follows:
• Signals A, B, and Z connect to the “H” (channel high) connectors on WBK17’s Counter Input
Terminal Blocks. A, B, and Z “highs” must be connected to separate channels.
• The input channel lows must be jumpered to COM.
• Each encoder ground connects to COM.
• Up to four encoders can be powered from the Encoder Power (Power Out) terminal block.
Refer to your encoder specification sheet for actual power requirements. Each encoder power
wire connects to the Encoder Power (Power Out) terminal block’s +15 VDC or +5 VDC
connector, as applicable.
For Differential Connections:
For differential applications, connections made from the encoder to the WBK17’s front panel are as
follows:
• Signals A, B, and Z connect to the “H” (channel high) connections on WBK17’s Counter
Input Terminal Blocks. A, B, and Z “highs” must be connected to separate channels.
• Signals /A, /B, and /Z connect to the respective “L” (channel low) connections on WBK17’s
Counter Input Terminal Blocks.
• Each encoder ground connects to COM.
• Up to four encoders can be powered from the Encoder Power (Power Out) terminal block.
Refer to your encoder specification sheet for actual power requirement. Each encoder power
wire connects to the Encoder Power (Power Out) terminal block’s +15 VDC or +5 VDC
connector, as applicable.
For Open-Collector Outputs: External pullup resistors can be connected to the WBK17’s
counter input terminal blocks. A pullup resistor can be placed between any input channel and one
of the two power supplies (+5V, or +15V) provided by the Encoder Power (Power Out) terminal
block. Choose a pullup resistor value based on the encoder’s output drive capability and the input
impedance of the WBK17. Lower values of pullup resistors will cause less distortion but also
cause the encoder’s output driver to pull down with more current. If the inputs are connected
differentially, then each channel will need two pullup resistors, i.e., one on the low signal input and
one on the high signal input.