USER MANUAL Manual

Parallel Port Communications 7–3
Publication 2706-6.1
The Parallel Port has connections for 4 strobe lines and 16 data lines.
KEYBOARD
SW1
SW2
GND
RELAY
L1 L2N
RS-485
250 VAC 3A
12VDC
RS-232
Parallel Port
The 4 strobe lines (MS0–MS3) specify the type of information on
the data lines (D0–D15).
For Message/Variable/Slave run mode, D0–D15 can receive:
• message number to trigger
• slave address to which message will be sent
• variables to be placed in message
– 16 bit binary
– 4 digit signed BCD
– l digit unsigned BCD
– 1 character ASCII
For Message List run mode, D0–D15 can receive:
• priority msg. number to trigger (interrupts message list)
• message number to add to message list
• message number to delete from message list
The following shows the relative significance of each data line.
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
MSB (Most Significant Bit) (Least Significant Bit ) LSB
Describing the Parallel Port