Racal Instruments 1260-82, User Manual

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1260-82 User Manual
Module Operation 3-8
Relay Data Status
Read Register
The 1260-82, via the Relay Data Status Register, provides a read
back of the position of each of the relays. This data uses the
same format as the Relay Control Register. When the bit is a 1 in
the status register, the corresponding relay is in the closed
position (COM n input connected to CH n1 output). When the bit
is a 0 in the status register, the COM n input is in the open
position (connected to the CH n0 output). Bit 0 holds the status
for channel 0, bit 1 holds the status for channel 1, and so on.
Note that since the status register reflects the ACTUAL relay
position, and not the COMMANDED relay position, this register
should not be used to form the relay control information when a
single channel change is desired. This means that a programmer
using the register-based mode should maintain a “RAM image” of
the desired states of the relays.
ERROR LED
Control Register
The ERROR LED Register controls the state of the 1260-82’s
ERROR LED. When the bit is set to a 1, the ERROR LED is
illuminated. When the bit is set to a 0, the ERROR LED is off.
The firmware normally controls this LED. When the confidence
mode is turned on, the firmware will turn the ERROR LED on if
the programmed state of each channel does not match the state
read back via the Relay Data Status register.
ERROR LED Register is located at (Module Base Address) + F
16
Relay
Control
Register Bit
Controls
0 (LSB) N/A
1 N/A
2 N/A
3 ERROR LED
4 N/A
5 N/A
6 N/A
7 (MSB) N/a