B-66 E6198B Switch/Load Unit User Manual
B Register Definitions
• Busy~: 0 indicates busy, 1 indicates not busy.
Write and Read Bits:
•OAR: 0 causes no change, 1 causes all relays to open
•GndRly: 0 opens relay from Inst2 to System Gnd (default), 1
closes relay from Inst2 to System Gnd
•DAC1Rly: 0 opens relay from Inst1 to DAC1 (default), 1
closes relay from Inst1 to DAC1
•DAC2Rly: 0 opens relay from Inst1 to DAC2 (default), 1
closes relay from Inst1 to DAC2
• Reset: 0 causes no change, 1 causes board reset and triggers
the relay timer. Clears itself afterward.
Not Used Base + 3
h
Register offset 3
h
used only for placeholder to make software
addressing simpler.
Abus control and protection bypass relay (W) Base + 4
h
Instrument matrix card Abus and protection bypass relay
control register. All relay control registers are positive-true
logic: writing 0 opens the relay and writing 1 closes the relay.
• Writing to PB4-PB1 sets state of protection bypass relays.
• Writing to AB4-AB1 sets state of Abus disconnect relays.
Not Used Base + 5
h
Register offser 5
h
used only for placeholder to make software
addressing simpler.
UUT Common to Instrument Bus
Instrument Relay 1-8 (W)
Base + 6
h
Bits76543210
Write
AB4 AB3 AB2 AB1 PB4 PB3 PB2 PB1
Bits76543210
Write
Inst
8
Inst
7
Inst
6
Inst
5
Inst
4
Inst
3
Inst
2
Inst
1