CommsMode

This optional parameter is left blank when used with the SDM-SIO1A or SDM-SIO4A. The CommsMode specifies the configuration of the datalogger's control port used by this instruction. The ports can also be configured using Device Configuration Utility. Configuring the ports using the SerialOpen instruction will change the setting if it was previously set by other means.

Code

Description
0 Configures the port as RS-232, ± 5V voltage levels (ComC1-ComC3, and CPI/RS-232 )
1 Configures the port as TTL, 5V and 0V voltage levels (ComC1-ComC3)
2 Configures the port as LVTTL, 3.3V and 0V voltage levels ( ComC1-ComC3 )
3 Configures the port as RS-485 half-duplex, PakBus communication (ComC1 or ComC3 only; Odd ports = A-; Even ports = B+)
4 Configures the port as RS-485 half-duplex, transparent (ComC1 or ComC3 only; Odd ports = A-; Even ports = B+)
5 Configures the port as RS-485 full-duplex (ComC1 only; requires 4 adjacent control ports, C1=TX-, C2 = TX+, C3=RX-, C4=RX+)
6 RS-485 transparent, TX only. In this configuration the transceiver is left on so the A(-) and B(+) ports idle in a marking state (logical '1').
7 RS-422 full-duplex transparent. In this configuration, the transceiver for the transmit pair is left on. The transmit pair A(-) and B(+) idle in a marking state (logical '1').
TIP: RS-422 protocol is similar to RS-485. Most RS-422 sensors will work with RS-485 protocol.