IDK MSD-5401 User Manual page 174

The received data without mask data and "AND" of each bit is compared with the reply command data. Set
"MASK" to "FF". Since "FF" is set by factory default, you do not need to change the mask data normally. Only
to determine the status using bits of the received data, change the setting.
[If ASCII codes (text) are replied from an external device]
Since the received data and "Reply command data" are compared without any changes, set "MASK" to "FF".
(If you set "COMMAND INPUT MODE" of reply command to "ASCII", it is automatically set to "FF".)
For example, if "0" of ASCII codes ("30" in hex) is replied:
(Received data)
(Reply command data)
DATA1:30 00 00 00 00
MASK1:FF FF FF FF FF
[If status is determined using bits of the received data]
Set only bits that determine the Mask data to "1" and set other bits to "0".
For example, if determining status using the second bit from the left:
(Received data)
(Reply command data)
(Received data)
(Reply command data)
DATA1:40 00 00 00 00
MASK1:40 FF FF FF FF
Binary
00110000 & (MASK)
00110000
Binary
11111111 & (MASK)
01000000
Binary
10111111 & (MASK)
01000000
174
MSD-54 SERIES User's Guide
Binary Hexadecimal
11111111 =30
=30 matched
Binary Hexadecimal
01000000 =40
=40 matched
Binary Hexadecimal
01000000 =00
=40 not matched