Each axis has a differential A, B and Z encoder input on J11 (Section 6.4), received by line receivers and counted by the motion IC.

Parameter

Value

Supported encoders

incremental encoders with RS-422 differential outputs (5 V line driver): A/A̅, B/B̅, Z/Z̅

Input voltage

any input pin must stay between 0 V and 4.0 V. Typical 5 V RS-422 drivers meet this when a 120 Ω termination resistor is fitted across each differential pair at J11 (external)

Termination

none on the board; fit 120 Ω across each pair (A–A̅, B–B̅, Z–Z̅) at J11 or on the JBD-50

Differential threshold

±100 mV

Maximum frequency

4.9 MHz line frequency, 19.7 M counts/s at ×4†; 1.6 MHz with the input noise filter enabled†

Count modes

×1, ×2, ×4 quadrature, or 2-pulse (up/down)

Encoder supply

+5 V on J11 pin 1, 200 mA maximum total for both encoders†; resettable fuse

Isolation

none: referenced to logic ground (J11 pin 2)

Wiring

Use twisted pairs for A/A̅, B/B̅ and Z/Z̅, with the encoder 0 V connected to J11 pin 2 (GND). Single-ended (TTL or open-collector) encoders are not supported: the inverting inputs are biased to +5 V on the board. Fit the external 120 Ω terminations at the receiving end.