Ma Current Loop Connections - GSE 60 SERIES Technical Reference Manual

13-38 Chapter 13
GSE Scale Systems
Figure 13-21: Label for 20mA COMM PORT pin designations
20 A P
M ARAMETER
The 20mA module does not have to be enabled in the setup mode. The
module simply converts the standard RS-232 communication on comm
port 1 to 20mA current loop.
20 A C
M URRENT
Apply the label over the silk screening on comm port 1 as previously
described ( J5 of the 460 Series or J6 of the 660 Series).
Transmit Current Input Active = TA
Transmit Current Input Passive = TP
Transmit Output = TXO
Receive Current Input = RXI
Receive Current Output = RX
The signal is bi-directional. Both the transmit output and the receive input
of the indicator are available as 20 mA signals. The handshaking signals
are not supported by the 20 mA current loop. Only baud rates of 9600 or
less are supported.
The TXO output may be used as an active or passive output from the
indicator. Either active or passive is chosen depending upon which
terminals are used for the connections. In active mode the indicator
supplies the current. In passive mode, the external device supplies the
current. The Rx input is available in passive mode only.
The input and output are electrically isolated from the main boards, earth
ground and each other. This applies for both passive and active modes.
Isolation is a minimum of 1000 volts.
The active mode transmit current loop provides a driving voltage of 12
VDC. This will allow 20 mA current flow with up to a 600 ohm load.
Passive mode will work with an external driving voltage of up to 50 VDC.
S
ETUP
L C
OOP ONNECTIONS